THE SACRAMENT OF CONFIRMATION
1285 Baptism, the Eucharist, and the sacrament of Confirmation together constitute the "sacraments of Christian initiation," whose unity must be safeguarded. It must be explained to the faithful that the reception of the sacrament of Confirmation is necessary for the completion of baptismal grace. [Cf. Roman Ritual, Rite of Confirmation (OC), Introduction 1.] For "by the sacrament of Confirmation, [the baptized] are more perfectly bound to the Church and are enriched with a special strength of the Holy Spirit. Hence they are, as true witnesses of Christ, more strictly obliged to spread and defend the faith by word and deed." [LG 11; Cf. OC, Introduction 2]
I. CONFIRMATION IN THE ECONOMY OF SALVATION
1286 In the Old Testament the prophets announced that the Spirit of the Lord would rest on the hoped-for Messiah for his saving mission. [Cf. Isa 11:2; 61:1; Lk 4:16-22] The descent of the Holy Spirit on Jesus at his baptism by John was the sign that this was he who was to come, the Messiah, the Son of God. [Cf. Mt 3:13-17; Jn 1:33-34] He was conceived of the Holy Spirit; his whole life and his whole mission are carried out in total communion with the Holy Spirit whom the Father gives him "without measure." [Jn 3:34] [702-716]
1287 This fullness of the Spirit was not to remain uniquely the Messiah's, but was to be communicated to the whole messianic people. [Cf. Ezek 36:25-27; Joel 3:1-2] On several occasions Christ promised this outpouring of the Spirit, [Cf. Lk 12:12; Jn 3:5-8; 7:37-39; 16:7-15; Acts 1:8] a promise which he fulfilled first on Easter Sunday and then more strikingly at Pentecost. [Cf. Jn 20:22; Acts 2:1-14] Filled with the Holy Spirit the apostles began to proclaim "the mighty works of God," and Peter declared this outpouring of the Spirit to be the sign of the messianic age. [Acts 2:11; Cf. 2:17-18] Those who believed in the apostolic preaching and were baptized received the gift of the Holy Spirit in their turn. [Cf. Acts 2:38] 
1288 "From that time on the apostles, in fulfillment of Christ's will, imparted to the newly baptized by the laying on of hands the gift of the Spirit that completes the grace of Baptism. For this reason in the Letter to the Hebrews the doctrine concerning Baptism and the laying on of hands is listed among the first elements of Christian instruction. The imposition of hands is rightly recognized by the Catholic tradition as the origin of the sacrament of Confirmation, which in a certain way perpetuates the grace of Pentecost in the Church." [Paul VI, Divinae consortium naturae, 659; Cf. Acts 8:15-17; 19:5-6; Heb 6:2] 
1289 Very early, the better to signify the gift of the Holy Spirit, an anointing with perfumed oil (chrism) was added to the laying on of hands. This anointing highlights the name "Christian," which means "anointed" and derives from that of Christ himself whom God "anointed with the Holy Spirit." [Acts 10:38] This rite of anointing has continued ever since, in both East and West. For this reason the Eastern Churches call this sacrament Chrismation, anointing with chrism, or myron which means "chrism." In the West, the term Confirmation suggests that this sacrament both confirms baptism and strengthens baptismal grace. [695, 436, 1297]
Two traditions: East and West
1290 In the first centuries Confirmation generally comprised one single celebration with Baptism, forming with it a "double sacrament," according to the expression of St. Cyprian. Among other reasons, the multiplication of infant baptisms all through the year, the increase of rural parishes, and the growth of dioceses often prevented the bishop from being present at all baptismal celebrations. In the West the desire to reserve the completion of Baptism to the bishop caused the temporal separation of the two sacraments. The East has kept them united, so that Confirmation is conferred by the priest who baptizes. But he can do so only with the "myron" consecrated by a bishop. [Cf. CCEO, Can. 695 § 1; 696 § 1] 
1291 A custom of the Roman Church facilitated the development of the Western practice: a double anointing with sacred chrism after Baptism. The first anointing of the neophyte on coming out of the baptismal bath was performed by the priest; it was completed by a second anointing on the forehead of the newly baptized by the bishop. [Cf. St. Hippolytus, Trad. Ap. 21 SCh 11, 80-95] The first anointing with sacred chrism, by the priest, has remained attached to the baptismal rite; it signifies the participation of the one baptized in the prophetic, priestly, and kingly offices of Christ. If Baptism is conferred on an adult, there is only one post-baptismal anointing, that of Confirmation. 
1292 The practice of the Eastern Churches gives greater emphasis to the unity of Christian initiation. That of the Latin Church more clearly expresses the communion of the new Christian with the bishop as guarantor and servant of the unity, catholicity and apostolicity of his Church, and hence the connection with the apostolic origins of Christ's Church. 
II. THE SIGNS AND THE RITE OF CONFIRMATION
1293 In treating the rite of Confirmation, it is fitting to consider the sign of anointing and what it signifies and imprints: a spiritual seal.
Anointing, in Biblical and other ancient symbolism, is rich in meaning: oil is a sign of abundance and joy; [Cf. Deut 11:14; Pss 23:5; 104:15] it cleanses (anointing before and after a bath) and limbers (the anointing of athletes and wrestlers); oil is a sign of healing, since it is soothing to bruises and wounds; [Cf. Isa 1:6; Lk 1034] and it makes radiant with beauty, health, and strength. 
1294 Anointing with oil has all these meanings in the sacramental life. The pre-baptismal anointing with the oil of catechumens signifies cleansing and strengthening; the anointing of the sick expresses healing and comfort. The post- baptismal anointing with sacred chrism in Confirmation and ordination is the sign of consecration. By Confirmation Christians, that is, those who are anointed, share more completely in the mission of Jesus Christ and the fullness of the Holy Spirit with which he is filled, so that their lives may give off "the aroma of Christ." [2 Cor 2:15] 
1295 By this anointing the confirmand receives the "mark," the seal of the Holy Spirit. A seal is a symbol of a person, a sign of personal authority, or ownership of an object. [Cf Gen 38:18; 41:42; Deut 32:34; CT 8:6] Hence soldiers were marked with their leader's seal and slaves with their master's. A seal authenticates a juridical act or document and occasionally makes it secret. [Cf. 1 Kings 21:8; Jer 32:10; Isa 29:11] 
1296 Christ himself declared that he was marked with his Father's seal. [Cf. Jn 6:27] Christians are also marked with a seal: "It is God who establishes us with you in Christ and has commissioned us; he has put his seal on us and given us his Spirit in our hearts as a guarantee." [2 Cor 1:21-22; cf. Eph 1:13; 4, 30] This seal of the Holy Spirit marks our total belonging to Christ, our enrollment in his service for ever, as well as the promise of divine protection in the great eschatological trial. [Cf. Rev 7:2-3; 9:4; Ezek 9:4-6] 
The celebration of Confirmation
1297 The consecration of the sacred chrism is an important action that precedes the celebration of Confirmation, but is in a certain way a part of it. It is the bishop who, in the course of the Chrism Mass of Holy Thursday, consecrates the sacred chrism for his whole diocese. In some Eastern Churches this consecration is even reserved to the patriarch: [1183, 1241]
The liturgy of Antioch expresses the epiclesis for the consecration of the sacred chrism (myron) in this way: "[Father... send your Holy Spirit] on us and on this oil which is before us and consecrate it, so that it may be for all who are anointed and marked with it holy myron, priestly myron, royal myron, anointing with gladness, clothing with light, a cloak of salvation, a spiritual gift, the sanctification of souls and bodies, imperishable happiness, the indelible seal, a buckler of faith, and a fearsome helmet against all the works of the adversary."
1298 When Confirmation is celebrated separately from Baptism, as is the case in the Roman Rite, the Liturgy of Confirmation begins with the renewal of baptismal promises and the profession of faith by the confirmands. This clearly shows that Confirmation follows Baptism. [Cf. SC 71] When adults are baptized, they immediately receive Confirmation and participate in the Eucharist. [Cf. CIC, can. 866]
1299 In the Roman Rite the bishop extends his hands over the whole group of the confirmands. Since the time of the apostles this gesture has signified the gift of the Spirit. The bishop invokes the outpouring of the Spirit in these words:
All-powerful God, Father of our Lord Jesus Christ,
by water and the Holy Spirit
you freed your sons and daughters from sin and gave them new life.
Send your Holy Spirit upon them
to be their helper and guide.
Give them the spirit of wisdom and understanding,
the spirit of right judgment and courage,
the spirit of knowledge and reverence.
Fill them with the spirit of wonder and awe in your presence.
We ask this through Christ our Lord.[OC 25] 
1300 The essential rite of the sacrament follows. In the Latin rite, "the sacrament of Confirmation is conferred through the anointing with chrism on the forehead, which is done by the laying on of the hand, and through the words: 'Accipe signaculum doni Spiritus Sancti' [Be sealed with the Gift of the Holy Spirit.]." [Paul VI, apostolic constitution, Divinae consortium naturae, 663] In the Eastern Churches of Byzantine, after a prayer of epiclesis the more significant parts of the body are anointed with myron: forehead, eyes, nose, ears, lips, breast, back, hands, and feet. Each anointing is accompanied by the formula SfragiV dwreaV PneumatoV ˘Agiou (Signaculum doni Spiritus Sancti): "the seal of the gift of the Holy Spirit. 
Rituale per le Chiese orientali di rito bizantino in lingua greca, Pars Prima (Libreria Editrice Vaticana, 1954) 36.
1301 The sign of peace that concludes the rite of the sacrament signifies and demonstrates ecclesial communion with the bishop and with all the faithful. [Cf. St. Hippolytus, Trad. Ap. 21 SCh 11, 80-95]
III. THE EFFECTS OF CONFIRMATION
1302 It is evident from its celebration that the effect of the sacrament of Confirmation is the special outpouring of the Holy Spirit as once granted to the apostles on the day of Pentecost. 
1303 From this fact, Confirmation brings an increase and deepening of baptismal grace: [1262-1274]
- it roots us more deeply in the divine filiation which makes us cry, "Abba! Father!"; [Rom 8:15]
- it unites us more firmly to Christ;
- it increases the gifts of the Holy Spirit in us;
- it renders our bond with the Church more perfect; [Cf. LG 11]
- it gives us a special strength of the Holy Spirit to spread and defend the faith by word and action as true witnesses of Christ, to confess the name of Christ boldly, and never to be ashamed of the Cross: [Cf. Council Of Florence (1439) DS 1319; LG 11; 12] 
Recall then that you have received the spiritual seal, the spirit of wisdom and understanding, the spirit of right judgment and courage, the spirit of knowledge and reverence, the spirit of holy fear in God's presence. Guard what you have received. God the Father has marked you with his sign; Christ the Lord has confirmed you and has placed his pledge, the Spirit, in your hearts. [SL Ambrose, De myst. 7, 42 PL 16, 402-403]
1304 Like Baptism which it completes, Confirmation is given only once, for it too imprints on the soul an indelible spiritual mark, the "character," which is the sign that Jesus Christ has marked a Christian with the seal of his Spirit by clothing him with power from on high so that he may be his witness. [Cf. Council Of Trent (1547) DS 1609; Lk 24:48-49] 
1305 This "character" perfects the common priesthood of the faithful, received in Baptism, and "the confirmed person receives the power to profess faith in Christ publicly and as it were officially (quasi ex officio)." [St. Thomas Aquinas, STh III, 72, 5, ad 2] 
IV. WHO CAN RECEIVE THIS SACRAMENT?
1306 Every baptized person not yet confirmed can and should receive the sacrament of Confirmation. [Cf. CIC, can. 889 § 1] Since Baptism, Confirmation, and Eucharist form a unity, it follows that "the faithful are obliged to receive this sacrament at the appropriate time," [CIC, can. 890] for without Confirmation and Eucharist, Baptism is certainly valid and efficacious, but Christian initiation remains incomplete. 
1307 For centuries, Latin custom has indicated "the age of discretion" as the reference point for receiving Confirmation. But in danger of death children should be confirmed even if they have not yet attained the age of discretion. [Cf. CIC, cann. 891; 883, 3]
1308 Although Confirmation is sometimes called the "sacrament of Christian maturity," we must not confuse adult faith with the adult age of natural growth, nor forget that the baptismal grace is a grace of free, unmerited election and does not need "ratification" to become effective. St. Thomas reminds us of this: 
Age of body does not determine age of soul. Even in childhood man can attain spiritual maturity: as the book of Wisdom says: "For old age is not honored for length of time, or measured by number of years. "Many children, through the strength of the Holy Spirit they have received, have bravely fought for Christ even to the shedding of their blood. [St. Thomas Aquinas, STh III, 72, 8, ad 2; Cf. Wis 4:8]
1309 Preparation for Confirmation should aim at leading the Christian toward a more intimate union with Christ and a more lively familiarity with the Holy Spirit - his actions, his gifts, and his biddings - in order to be more capable of assuming the apostolic responsibilities of Christian life. To this end catechesis for Confirmation should strive to awaken a sense of belonging to the Church of Jesus Christ, the universal Church as well as the parish community. The latter bears special responsibility for the preparation of confirmands. [Cf. OC Introduction 3]
1310 To receive Confirmation one must be in a state of grace. One should receive the sacrament of Penance in order to be cleansed for the gift of the Holy Spirit. More intense prayer should prepare one to receive the strength and graces of the Holy Spirit with docility and readiness to act. [Cf. Acts 1:14] 
1311 Candidates for Confirmation, as for Baptism, fittingly seek the spiritual help of a sponsor. To emphasize the unity of the two sacraments, it is appropriate that this be one of the baptismal godparents. [Cf. OC Introduction 5; 6; CIC, Can. 893 §§ 1- 2] 
V. THE MINISTER OF CONFIRMATION
1312 The original minister of Confirmation is the bishop. [Cf. LG 26] 
In the East, ordinarily the priest who baptizes also immediately confers Confirmation in one and the same celebration. But he does so with sacred chrism consecrated by the patriarch or the bishop, thus expressing the apostolic unity of the Church whose bonds are strengthened by the sacrament of Confirmation. In the Latin Church, the same discipline applies to the Baptism of adults or to the reception into full communion with the Church of a person baptized in another Christian community that does not have valid Confirmation. [Cf. CIC, Can. 883 § 2]
1313 In the Latin Rite, the ordinary minister of Confirmation is the bishop. [Cf. CIC, Can. 882] If the need arises, the bishop may gran the faculty of administering confirmation to priests, although it is fitting that he confer it himself, mindful that the celebration of Confirmation has been temporally separated from Baptism for this reason. Bishops are the successors of the apostles. They have received the fullness of the sacrament of Holy Orders. The administration of this sacrament by them demonstrates clearly that its effect is to unite those who receive it more closely to the Church, to her apostolic origins, and to her mission of bearing witness to Christ. [Cf. CIC, Can. 884 § 2] [1290, 1285]
1314 If a Christian is in danger of death, any priest can give him Confirmation. [Cf. CIC, Can. 883 § 3] Indeed the Church desires that none of her children, even the youngest, should depart this world without having been perfected by the Holy Spirit with the gift of Christ's fullness. 
1315 "Now when the apostles at Jerusalem heard that Samaria had received the word of God, they sent to them Peter and John, who came down and prayed for them that they might receive the Holy Spirit; for it had not yet fallen on any of them, but they had only been baptized in the name of the Lord Jesus. Then they laid their hands on them and they received the Holy Spirit" (Acts 8:14-17).
1316 Confirmation perfects Baptismal grace; it is the sacrament which gives the Holy Spirit in order to root us more deeply in the divine filiation, incorporate us more firmly into Christ, strengthen our bond with the Church, associate us more closely with her mission, and help us bear witness to the Christian faith in words accompanied by deeds.
1317 Confirmation, like Baptism, imprints a spiritual mark or indelible character on the Christian's soul; for this reason one can receive this sacrament only once in one's life.
1318 In the East this sacrament is administered immediately after Baptism and is followed by participation in the Eucharist; this tradition highlights the unity of the three sacraments of Christian initiation. In the Latin Church this sacrament is administered when the age of reason has been reached, and its celebration is ordinarily reserved to the bishop, thus signifying that this sacrament strengthens the ecclesial bond.
1319 A candidate for Confirmation who has attained the age of reason must profess the faith, be in the state of grace, have the intention of receiving the sacrament, and be prepared to assume the role of disciple and witness to Christ, both within the ecclesial community and in temporal affairs.
1320 The essential rite of Confirmation is anointing the forehead of the baptized with sacred chrism (in the East other sense-organs as well), together with the laying on of the minister's hand and the words: "Accipe signaculum doni Spiritus Sancti" (Be sealed with the Gift of the Holy Spirit.) in the Roman Rite, or: Signaculum doni Spiritus Sancti [the seal of the gift of the Holy Spirit] in the Byzantine rite. 1321 When Confirmation is celebrated separately from Baptism, its connection with Baptism is expressed, among other ways, by the renewal of baptismal promises. The celebration of Confirmation during the Eucharist helps underline the unity of the sacraments of Christian initiation.
THE SACRAMENT OF THE EUCHARIST
1322 The holy Eucharist completes Christian initiation. Those who have been raised to the dignity of the royal priesthood by Baptism and configured more deeply to Christ by Confirmation participate with the whole community in the Lord's own sacrifice by means of the Eucharist. 
1323 "At the Last Supper, on the night he was betrayed, our Savior instituted the Eucharistic sacrifice of his Body and Blood. This he did in order to perpetuate the sacrifice of the cross throughout the ages until he should come again, and so to entrust to his beloved Spouse, the Church, a memorial of his death and resurrection: a sacrament of love, a sign of unity, a bond of charity, a Paschal banquet 'in which Christ is consumed, the mind is filled with grace, and a pledge of future glory is given to us.'" [SC 47] 
I. THE EUCHARIST - SOURCE AND SUMMIT OF ECCLESIAL LIFE
1324 The Eucharist is "the source and summit of the Christian life." [LG 11] "The other sacraments, and indeed all ecclesiastical ministries and works of the apostolate, are bound up with the Eucharist and are oriented toward it. For in the blessed Eucharist is contained the whole spiritual good of the Church, namely Christ himself, our Pasch." [PO 5] 
1325 "The Eucharist is the efficacious sign and sublime cause of that communion in the divine life and that unity of the People of God by which the Church is kept in being. It is the culmination both of God's action sanctifying the world in Christ and of the worship men offer to Christ and through him to the Father in the Holy Spirit." [Congregation of Rites, instruction, Eucharisticum mysterium, 6] 
1326 Finally, by the Eucharistic celebration we already unite ourselves with the heavenly liturgy and anticipate eternal life, when God will be all in all. [Cf. 1 Cor 15:28] 
1327 In brief, the Eucharist is the sum and summary of our faith: "Our way of thinking is attuned to the Eucharist, and the Eucharist in turn confirms our way of thinking." [St. Irenaeus, Adv. haeres. 4, 18, 5: PG 7/l, 1028] 
II. WHAT IS THIS SACRAMENT CALLED?
1328 The inexhaustible richness of this sacrament is expressed in the different names we give it. Each name evokes certain aspects of it. It is called:
Eucharist, because it is an action of thanksgiving to God. The Greek words eucharistein [Cf. Lk 22:19; 1 Cor 11:24] and eulogein [Cf. Mt 26:26; Mk 14:22] recall the Jewish blessings that proclaim - especially during a meal - God's works: creation, redemption, and sanctification. [2637, 1082, 1359]
1329 The Lord's Supper, because of its connection with the supper which the Lord took with his disciples on the eve of his Passion and because it anticipates the wedding feast of the Lamb in the heavenly Jerusalem. [Cf. 1 Cor 11:20; Rev 19:9] 
The Breaking of Bread, because Jesus used this rite, part of a Jewish meat when as master of the table he blessed and distributed the bread, [Cf. Mt 14:19; 15:36; Mk 8:6, 19] above all at the Last Supper. [Cf. Mt 26:26; 1 Cor 11:24] It is by this action that his disciples will recognize him after his Resurrection, [Cf. Lk 24:13-35] and it is this expression that the first Christians will use to designate their Eucharistic assemblies; [Cf. Acts 2:42, 46; 20:7, 11] by doing so they signified that all who eat the one broken bread, Christ, enter into communion with him and form but one body in him. [Cf. 1 Cor 10:16-17] 
The Eucharistic assembly (synaxis), because the Eucharist is celebrated amid the assembly of the faithful, the visible expression of the Church. [Cf. 1 Cor 11:17-34] 
1330 The memorial of the Lord's Passion and Resurrection. 
The Holy Sacrifice, because it makes present the one sacrifice of Christ the Savior and includes the Church's offering. The terms holy sacrifice of the Mass, "sacrifice of praise," spiritual sacrifice, pure and holy sacrifice are also used, [Heb 13:15; cf. 1 Pet 25; Ps 116:13, 17; Mal 1:11] since it completes and surpasses all the sacrifices of the Old Covenant. [614, 2643]
The Holy and Divine Liturgy, because the Church's whole liturgy finds its center and most intense expression in the celebration of this sacrament; in the same sense we also call its celebration the Sacred Mysteries. We speak of the Most Blessed Sacrament because it is the Sacrament of sacraments. The Eucharistic species reserved in the tabernacle are designated by this same name. 
1331 Holy Communion, because by this sacrament we unite ourselves to Christ, who makes us sharers in his Body and Blood to form a single body. [Cf. 1 Cor 1016-17] We also call it: the holy things (ta hagia; sancta) [Apostolic Constitutions 8, 13,12 PG 1,1108; Didache 9, 5; 10:6: SCh: 248,176- 178] - the first meaning of the phrase "communion of saints" in the Apostles' Creed - the bread of angels, bread from heaven, medicine of immortality, [St. Ignatius of Antioch, Ad Eph. 20, 2 SCh 10, 76] viaticum.... [950, 948, 1405]
1332 Holy Mass (Missa), because the liturgy in which the mystery of salvation is accomplished concludes with the sending forth (missio) of the faithful, so that they may fulfill God's will in their daily lives. 
III. THE EUCHARIST IN THE ECONOMY OF SALVATION
The signs of bread and wine
1333 At the heart of the Eucharistic celebration are the bread and wine that, by the words of Christ and the invocation of the Holy Spirit, become Christ's Body and Blood. Faithful to the Lord's command the Church continues to do, in his memory and until his glorious return, what he did on the eve of his Passion: "He took bread...." "He took the cup filled with wine...." The signs of bread and wine become, in a way surpassing understanding, the Body and Blood of Christ; they continue also to signify the goodness of creation. Thus in the Offertory we give thanks to the Creator for bread and wine, [Cf. Ps 104:13-15] fruit of the "work of human hands," but above all as "fruit of the earth" and "of the vine" - gifts of the Creator. The Church sees in the gesture of the king-priest Melchizedek, who "brought out bread and wine," a prefiguring of her own offering. [Gen 14:18; cf. Roman Missal, EP I (Roman Canon) 95] [1350, 1147, 1148]
1334 In the Old Covenant bread and wine were offered in sacrifice among the first fruits of the earth as a sign of grateful acknowledgment to the Creator. But they also received a new significance in the context of the Exodus: the unleavened bread that Israel eats every year at Passover commemorates the haste of the departure that liberated them from Egypt; the remembrance of the manna in the desert will always recall to Israel that it lives by the bread of the Word of God; [Cf. Deut 8:3] their daily bread is the fruit of the promised land, the pledge of God's faithfulness to his promises. The "cup of blessing" [1 Cor 10:16] at the end of the Jewish Passover meal adds to the festive joy of wine an eschatological dimension: the messianic expectation of the rebuilding of Jerusalem. When Jesus instituted the Eucharist, he gave a new and definitive meaning to the blessing of the bread and the cup. [1150, 1363]
1335 The miracles of the multiplication of the loaves, when the Lord says the blessing, breaks and distributes the loaves through his disciples to feed the multitude, prefigure the superabundance of this unique bread of his Eucharist. [Cf. Mt 14:13-21; 15:32-39] The sign of water turned into wine at Cana already announces the Hour of Jesus' glorification. It makes manifest the fulfillment of the wedding feast in the Father's kingdom, where the faithful will drink the new wine that has become the Blood of Christ. [Cf. Jn 2:11; Mk 14:25] 
1336 The first announcement of the Eucharist divided the disciples, just as the announcement of the Passion scandalized them: "This is a hard saying; who can listen to it?" [Jn 6:60] The Eucharist and the Cross are stumbling blocks. It is the same mystery and it never ceases to be an occasion of division. "Will you also go away?": [Jn 6:67] the Lord's question echoes through the ages, as a loving invitation to discover that only he has "the words of eternal life" [Jn 6:68] and that to receive in faith the gift of his Eucharist is to receive the Lord himself. 
The institution of the Eucharist
1337 The Lord, having loved those who were his own, loved them to the end. Knowing that the hour had come to leave this world and return to the Father, in the course of a meal he washed their feet and gave them the commandment of love. [Cf. Jn 13:1-17; 34-35] In order to leave them a pledge of this love, in order never to depart from his own and to make them sharers in his Passover, he instituted the Eucharist as the memorial of his death and Resurrection, and commanded his apostles to celebrate it until his return; "thereby he constituted them priests of the New Testament." [Council of Trent (1562): DS 1740] [610, 611]
1338 The three synoptic Gospels and St. Paul have handed on to us the account of the institution of the Eucharist; St. John, for his part, reports the words of Jesus in the synagogue of Capernaum that prepare for the institution of the Eucharist: Christ calls himself the bread of life, come down from heaven. [Cf. Jn 6]
1339 Jesus chose the time of Passover to fulfill what he had announced at Capernaum: giving his disciples his Body and his Blood: 
Then came the day of Unleavened Bread, on which the passover lamb had to be sacrificed. So Jesus sent Peter and John, saying, "Go and prepare the passover meal for us, that we may eat it...." They went ... and prepared the passover. And when the hour came, he sat at table, and the apostles with him. And he said to them, "I have earnestly desired to eat this passover with you before I suffer; for I tell you I shall not eat it again until it is fulfilled in the kingdom of God.".... And he took bread, and when he had given thanks he broke it and gave it to them, saying, "This is my body which is given for you. Do this in remembrance of me." And likewise the cup after supper, saying, "This cup which is poured out for you is the New Covenant in my blood." [Lk 22:7-20; Cf. Mt 26:17-29; Mk 14:12-25; 1 Cor 11:23-26]
1340 By celebrating the Last Supper with his apostles in the course of the Passover meal, Jesus gave the Jewish Passover its definitive meaning. Jesus' passing over to his father by his death and Resurrection, the new Passover, is anticipated in the Supper and celebrated in the Eucharist, which fulfills the Jewish Passover and anticipates the final Passover of the Church in the glory of the kingdom. [1151, 677]
"Do this in memory of me"
1341 The command of Jesus to repeat his actions and words "until he comes" does not only ask us to remember Jesus and what he did. It is directed at the liturgical celebration, by the apostles and their successors, of the memorial of Christ, of his life, of his death, of his Resurrection, and of his intercession in the presence of the Father. [Cf. 2 Cor 11:26] [611, 
1342 From the beginning the Church has been faithful to the Lord's command. Of the Church of Jerusalem it is written: 
They devoted themselves to the apostles' teaching and fellowship, to the breaking of bread and the prayers.... Day by day, attending the temple together and breaking bread in their homes, they partook of food with glad and generous hearts. [Acts 2:42, 46]
1343 It was above all on "the first day of the week," Sunday, the day of Jesus' resurrection, that the Christians met "to break bread." [Acts 20:7] From that time on down to our own day the celebration of the Eucharist has been continued so that today we encounter it everywhere in the Church with the same fundamental structure. It remains the center of the Church's life. [1166, 2177]
1344 Thus from celebration to celebration, as they proclaim the Paschal mystery of Jesus "until he comes," the pilgrim People of God advances, "following the narrow way of the cross," [AG 1; cf. 1 Cor 11:26] toward the heavenly banquet, when all the elect will be seated at the table of the kingdom. 
IV. THE LITURGICAL CELEBRATION OF THE EUCHARIST
The Mass of all ages
1345 As early as the second century we have the witness of St. Justin Martyr for the basic lines of the order of the Eucharistic celebration. They have stayed the same until our own day for all the great liturgical families. St. Justin wrote to the pagan emperor Antoninus Pius (138-161) around the year 155, explaining what Christians did:
On the day we call the day of the sun, all who dwell in the city or country gather in the same place.
The memoirs of the apostles and the writings of the prophets are read, as much as time permits.
When the reader has finished, he who presides over those gathered admonishes and challenges them to imitate these beautiful things.
Then we all rise together and offer prayers* for ourselves... and for all others, wherever they may be, so that we may be found righteous by our life and actions, and faithful to the commandments, so as to obtain eternal salvation.
When the prayers are concluded we exchange the kiss.
Then someone brings bread and a cup of water and wine mixed together to him who presides over the brethren.
He takes them and offers praise and glory to the Father of the universe, through the name of the Son and of the Holy Spirit and for a considerable time he gives thanks (in Greek: eucharistian) that we have been judged worthy of these gifts.
When he has concluded the prayers and thanksgivings, all present give voice to an acclamation by saying: 'Amen.'
When he who presides has given thanks and the people have responded, those whom we call deacons give to those present the "eucharisted" bread, wine and water and take them to those who are absent. [St. Justin, Apol. 1, 65-67: PG 6, 428-429; the text before the asterisk (*) is from chap. 67]
1346 The liturgy of the Eucharist unfolds according to a fundamental structure which has been preserved throughout the centuries down to our own day. It displays two great parts that form a fundamental unity:
- the gathering, the liturgy of the Word, with readings, homily and general intercessions;
- the liturgy of the Eucharist, with the presentation of the bread and wine, the consecratory thanksgiving, and communion.
The liturgy of the Word and liturgy of the Eucharist together form "one single act of worship"; [SC 56] the Eucharistic table set for us is the table both of the Word of God and of the Body of the Lord. [Cf. DV 21] 
1347 Is this not the same movement as the Paschal meal of the risen Jesus with his disciples? Walking with them he explained the Scriptures to them; sitting with them at table "he took bread, blessed and broke it, and gave it to them." [Cf. Lk 24:13-35]
The movement of the celebration
1348 All gather together. Christians come together in one place for the Eucharistic assembly. At its head is Christ himself, the principal agent of the Eucharist. He is high priest of the New Covenant; it is he himself who presides invisibly over every Eucharistic celebration. It is in representing him that the bishop or priest acting in the person of Christ the head (in persona Christi capitis) presides over the assembly, speaks after the readings, receives the offerings, and says the Eucharistic Prayer. All have their own active parts to play in the celebration, each in his own way: readers, those who bring up the offerings, those who give communion, and the whole people whose "Amen" manifests their participation. [1140, 1548]
1349 The Liturgy of the Word includes "the writings of the prophets," that is, the Old Testament, and "the memoirs of the apostles" (their letters and the Gospels). After the homily, which is an exhortation to accept this Word as what it truly is, the Word of God, [Cf. 1 Thess 2:13] and to put it into practice, come the intercessions for all men, according to the Apostle's words: "I urge that supplications, prayers, intercessions, and thanksgivings be made for all men, for kings, and all who are in high positions." [1 Tim 2:1-2] 
1350 The presentation of the offerings (the Offertory). Then, sometimes in procession, the bread and wine are brought to the altar; they will be offered by the priest in the name of Christ in the Eucharistic sacrifice in which they will become his body and blood. It is the very action of Christ at the Last Supper - "taking the bread and a cup." "The Church alone offers this pure oblation to the Creator, when she offers what comes forth from his creation with thanksgiving." [St. Irenaeus, Adv. haeres. 4, 18, 4: PG 7/1, 1027; cf. Mal 1:11] The presentation of the offerings at the altar takes up the gesture of Melchizedek and commits the Creator's gifts into the hands of Christ who, in his sacrifice, brings to perfection all human attempts to offer sacrifices. [1359, 614]
1351 From the very beginning Christians have brought, along with the bread and wine for the Eucharist, gifts to share with those in need. This custom of the collection, ever appropriate, is inspired by the example of Christ who became poor to make us rich: [Cf. 1 Cor 16:1; 2 Cor 8:9] [1397, 2186]
Those who are well off, and who are also willing, give as each chooses. What is gathered is given to him who presides to assist orphans and widows, those whom illness or any other cause has deprived of resources, prisoners, immigrants and, in a word, all who are in need. [St. Justin, Apol. 1, 67: PG 6, 429]
1352 The anaphora: with the Eucharistic Prayer - the prayer of thanksgiving and consecration - we come to the heart and summit of the celebration:
In the preface, the Church gives thanks to the Father, through Christ, in the Holy Spirit, for all his works: creation, redemption, and sanctification. The whole community thus joins in the unending praise that the Church in heaven, the angels and all the saints, sing to the thrice-holy God. 
1353 In the epiclesis, the Church asks the Father to send his Holy Spirit (or the power of his blessing [Cf. Roman Missal, EP I (Roman Canon) 90] ) on the bread and wine, so that by his power they may become the body and blood of Jesus Christ and so that those who take part in the Eucharist may be one body and one spirit (some liturgical traditions put the epiclesis after the anamnesis). 
In the institution narrative, the power of the words and the action of Christ, and the power of the Holy Spirit, make sacramentally present under the species of bread and wine Christ's body and blood, his sacrifice offered on the cross once for all. 
1354 In the anamnesis that follows, the Church calls to mind the Passion, resurrection, and glorious return of Christ Jesus; she presents to the Father the offering of his Son which reconciles us with him. 
In the intercessions, the Church indicates that the Eucharist is celebrated in communion with the whole Church in heaven and on earth, the living and the dead, and in communion with the pastors of the Church, the Pope, the diocesan bishop, his presbyterium and his deacons, and all the bishops of the whole world together with their Churches. 
1355 In the communion, preceded by the Lord's prayer and the breaking of the bread, the faithful receive "the bread of heaven" and "the cup of salvation," the body and blood of Christ who offered himself "for the life of the world": [Jn 6:51] 
Because this bread and wine have been made Eucharist ("eucharisted," according to an ancient expression), "we call this food Eucharist, and no one may take part in it unless he believes that what we teach is true, has received baptism for the forgiveness of sins and new birth, and lives in keeping with what Christ taught." [St. Justin, Apol. 1, 66,1-2: PG 6, 428] 
V. THE SACRAMENTAL SACRIFICE THANKSGIVING, MEMORIAL, PRESENCE
1356 If from the beginning Christians have celebrated the Eucharist and in a form whose substance has not changed despite the great diversity of times and liturgies, it is because we know ourselves to be bound by the command the Lord gave on the eve of his Passion: "Do this in remembrance of me." [1 Cor 11:24-25]
1357 We carry out this command of the Lord by celebrating the memorial of his sacrifice. In so doing, we offer to the Father what he has himself given us: the gifts of his creation, bread and wine which, by the power of the Holy Spirit and by the words of Christ, have become the body and blood of Christ. Christ is thus really and mysteriously made present.
1358 We must therefore consider the Eucharist as:
- thanksgiving and praise to the Father;
- the sacrificial memorial of Christ and his Body;
- the presence of Christ by the power of his word and of his Spirit.
Thanksgiving and praise to the Father
1359 The Eucharist, the sacrament of our salvation accomplished by Christ on the cross, is also a sacrifice of praise in thanksgiving for the work of creation. In the Eucharistic sacrifice the whole of creation loved by God is presented to the Father through the death and the Resurrection of Christ. Through Christ the Church can offer the sacrifice of praise in thanksgiving for all that God has made good, beautiful, and just in creation and in humanity. 
1360 The Eucharist is a sacrifice of thanksgiving to the Father, a blessing by which the Church expresses her gratitude to God for all his benefits, for all that he has accomplished through creation, redemption, and sanctification. Eucharist means first of all "thanksgiving." 
1361 The Eucharist is also the sacrifice of praise by which the Church sings the glory of God in the name of all creation. This sacrifice of praise is possible only through Christ: he unites the faithful to his person, to his praise, and to his intercession, so that the sacrifice of praise to the Father is offered through Christ and with him, to be accepted in him. 
The sacrificial memorial of Christ and of his Body, the Church
1362 The Eucharist is the memorial of Christ's Passover, the making present and the sacramental offering of his unique sacrifice, in the liturgy of the Church which is his Body. In all the Eucharistic Prayers we find after the words of institution a prayer called the anamnesis or memorial. 
1363 In the sense of Sacred Scripture the memorial is not merely the recollection of past events but the proclamation of the mighty works wrought by God for men. [Cf. Ex 13:3] In the liturgical celebration of these events, they become in a certain way present and real. This is how Israel understands its liberation from Egypt: every time Passover is celebrated, the Exodus events are made present to the memory of believers so that they may conform their lives to them.
1364 In the New Testament, the memorial takes on new meaning. When the Church celebrates the Eucharist, she commemorates Christ's Passover, and it is made present the sacrifice Christ offered once for all on the cross remains ever present. [Cf. Heb 7:25-27] "As often as the sacrifice of the Cross by which 'Christ our Pasch has been sacrificed' is celebrated on the altar, the work of our redemption is carried out." [LG 3; cf. 1 Cor 5:7] [611, 1085]
1365 Because it is the memorial of Christ's Passover, the Eucharist is also a sacrifice. The sacrificial character of the Eucharist is manifested in the very words of institution: "This is my body which is given for you" and "This cup which is poured out for you is the New Covenant in my blood." [Lk 22:19-20] In the Eucharist Christ gives us the very body which he gave up for us on the cross, the very blood which he "poured out for many for the forgiveness of sins." [Mt 26:28] [2100, 1846]
1366 The Eucharist is thus a sacrifice because it re-presents (makes present) the sacrifice of the cross, because it is its memorial and because it applies its fruit: 
[Christ], our Lord and God, was once and for all to offer himself to God the Father by his death on the altar of the cross, to accomplish there an everlasting redemption. But because his priesthood was not to end with his death, at the Last Supper "on the night when he was betrayed," [he wanted] to leave to his beloved spouse the Church a visible sacrifice (as the nature of man demands) by which the bloody sacrifice which he was to accomplish once for all on the cross would be re-presented, its memory perpetuated until the end of the world, and its salutary power be applied to the forgiveness of the sins we daily commit. [Council of Trent (1562): DS 1740; cf. 1 Cor 11:23; Heb 7:24, 27]
1367 The sacrifice of Christ and the sacrifice of the Eucharist are one single sacrifice: "The victim is one and the same: the same now offers through the ministry of priests, who then offered himself on the cross; only the manner of offering is different." "And since in this divine sacrifice which is celebrated in the Mass, the same Christ who offered himself once in a bloody manner on the altar of the cross is contained and offered in an unbloody manner . . . this sacrifice is truly propitiatory." [Council of Trent (1562) Doctrinia de ss. Missae sacrificio, c. 2DS 1743; cf. Heb 9:14, 27]
1368 The Eucharist is also the sacrifice of the Church. The Church which is the Body of Christ participates in the offering of her Head. With him, she herself is offered whole and entire. She unites herself to his intercession with the Father for all men. In the Eucharist the sacrifice of Christ becomes also the sacrifice of the members of his Body. The lives of the faithful, their praise, sufferings, prayer, and work, are united with those of Christ and with his total offering, and so acquire a new value. Christ's sacrifice present on the altar makes it possible for all generations of Christians to be united with his offering. [618, 2031, 1109]
In the catacombs the Church is often represented as a woman in prayer, arms outstretched in the praying position. Like Christ who stretched out his arms on the cross, through him, with him, and in him, she offers herself and intercedes for all men.
1369 The whole Church is united with the offering and intercession of Christ. Since he has the ministry of Peter in the Church, the Pope is associated with every celebration of the Eucharist, wherein he is named as the sign and servant of the unity of the universal Church. The bishop of the place is always responsible for the Eucharist, even when a priest presides; the bishop's name is mentioned to signify his presidency over the particular Church, in the midst of his presbyterium and with the assistance of deacons. The community intercedes also for all ministers who, for it and with it, offer the Eucharistic sacrifice: [834, 882, 1561, 1566]
Let only that Eucharist be regarded as legitimate, which is celebrated under [the presidency of] the bishop or him to whom he has entrusted it. [St. Ignatius of Antioch, Ad Smyrn. 8:1; SCh 10, 138] Through the ministry of priests the spiritual sacrifice of the faithful is completed in union with the sacrifice of Christ the only Mediator, which in the Eucharist is offered through the priests' hands in the name of the whole Church in an unbloody and sacramental manner until the Lord himself comes. [PO 2 § 4]
1370 To the offering of Christ are united not only the members still here on earth, but also those already in the glory of heaven. In communion with and commemorating the Blessed Virgin Mary and all the saints, the Church offers the Eucharistic sacrifice. In the Eucharist the Church is as it were at the foot of the cross with Mary, united with the offering and intercession of Christ. [956, 969]
1371 The Eucharistic sacrifice is also offered for the faithful departed who "have died in Christ but are not yet wholly purified," [Council of Trent (1562) DS 1743] so that they may be able to enter into the light and peace of Christ: [958, 1689, 1032]
Put this body anywhere! Don't trouble yourselves about it! I simply ask you to remember me at the Lord's altar wherever you are. [St. Monica, before her death, to her sons, St. Augustine and his brother; Conf. 9, 11, 27: PL 32, 775]
Then, we pray [in the anaphora] for the holy fathers and bishops who have fallen asleep, and in general for all who have fallen asleep before us, in the belief that it is a great benefit to the souls on whose behalf the supplication is offered, while the holy and tremendous Victim is present.... By offering to God our supplications for those who have fallen asleep, if they have sinned, we... offer Christ sacrificed for the sins of all, and so render favorable, for them and for us, the God who loves man. [St. Cyril of Jerusalem, Catech. myst. 5, 9. 10 PG 33, 1116-1117]
1372 St. Augustine admirably summed up this doctrine that moves us to an ever more complete participation in our Redeemer's sacrifice which we celebrate in the Eucharist: 
This wholly redeemed city, the assembly and society of the saints, is offered to God as a universal sacrifice by the high priest who in the form of a slave went so far as to offer himself for us in his Passion, to make us the Body of so great a head.... Such is the sacrifice of Christians: "we who are many are one Body in Christ" The Church continues to reproduce this sacrifice in the sacrament of the altar so well-known to believers wherein it is evident to them that in what she offers she herself is offered. [St. Augustine, De civ Dei, 10, 6: PL 41, 283; cf. Rom 12:5]
The presence of Christ by the power of his word and the Holy Spirit
1373 "Christ Jesus, who died, yes, who was raised from the dead, who is at the right hand of God, who indeed intercedes for us," is present in many ways to his Church: [Rom 8:34; cf. LG 48] in his word, in his Church's prayer, "where two or three are gathered in my name," [Mt 18:20] in the poor, the sick, and the imprisoned, [Cf. Mt 25:31-46] in the sacraments of which he is the author, in the sacrifice of the Mass, and in the person of the minister. But "he is present... most especially in the Eucharistic species." [SC 7] 
1374 The mode of Christ's presence under the Eucharistic species is unique. It raises the Eucharist above all the sacraments as "the perfection of the spiritual life and the end to which all the sacraments tend." [St. Thomas Aquinas, STh III, 73, 3c] In the most blessed sacrament of the Eucharist "the body and blood, together with the soul and divinity, of our Lord Jesus Christ and, therefore, the whole Christ is truly, really, and substantially contained." [Council of Trent (1551): DS 1651] "This presence is called 'real' - by which is not intended to exclude the other types of presence as if they could not be 'real' too, but because it is presence in the fullest sense: that is to say, it is a substantial presence by which Christ, God and man, makes himself wholly and entirely present." [Paul VI, MF 39] 
1375 It is by the conversion of the bread and wine into Christ's body and blood that Christ becomes present in this sacrament. The Church Fathers strongly affirmed the faith of the Church in the efficacy of the Word of Christ and of the action of the Holy Spirit to bring about this conversion. Thus St. John Chrysostom declares: 
It is not man that causes the things offered to become the Body and Blood of Christ, but he who was crucified for us, Christ himself. The priest, in the role of Christ, pronounces these words, but their power and grace are God's. This is my body, he says. This word transforms the things offered. [St. John Chrysostom, prod. Jud. 1:6: PG 49, 380] 
And St. Ambrose says about this conversion:
Be convinced that this is not what nature has formed, but what the blessing has consecrated. The power of the blessing prevails over that of nature, because by the blessing nature itself is changed.... Could not Christ's word, which can make from nothing what did not exist, change existing things into what they were not before? It is no less a feat to give things their original nature than to change their nature. [St. Ambrose, De myst. 9, 50; 52: PL 16, 405-407] 
1376 The Council of Trent summarizes the Catholic faith by declaring: "Because Christ our Redeemer said that it was truly his body that he was offering under the species of bread, it has always been the conviction of the Church of God, and this holy Council now declares again, that by the consecration of the bread and wine there takes place a change of the whole substance of the bread into the substance of the body of Christ our Lord and of the whole substance of the wine into the substance of his blood. This change the holy Catholic Church has fittingly and properly called transubstantiation." [Council of Trent (1551): DS 1642; cf. Mt 26:26 ff.; Mk 14:22 ff.; Lk 22:19 ff.; 1 Cor 11:24 ff]
1377 The Eucharistic presence of Christ begins at the moment of the consecration and endures as long as the Eucharistic species subsist. Christ is present whole and entire in each of the species and whole and entire in each of their parts, in such a way that the breaking of the bread does not divide Christ. [Cf. Council of Trent: DS 1641]
1378 Worship of the Eucharist. In the liturgy of the Mass we express our faith in the real presence of Christ under the species of bread and wine by, among other ways, genuflecting or bowing deeply as a sign of adoration of the Lord. "The Catholic Church has always offered and still offers to the sacrament of the Eucharist the cult of adoration, not only during Mass, but also outside of it, reserving the consecrated hosts with the utmost care, exposing them to the solemn veneration of the faithful, and carrying them in procession." [Paul VI, MF 56] [1178, 103, 2628]
1379 The tabernacle was first intended for the reservation of the Eucharist in a worthy place so that it could be brought to the sick and those absent outside of Mass. As faith in the real presence of Christ in his Eucharist deepened, the Church became conscious of the meaning of silent adoration of the Lord present under the Eucharistic species. It is for this reason that the tabernacle should be located in an especially worthy place in the church and should be constructed in such a way that it emphasizes and manifests the truth of the real presence of Christ in the Blessed Sacrament. [1183, 2691]
1380 It is highly fitting that Christ should have wanted to remain present to his Church in this unique way. Since Christ was about to take his departure from his own in his visible form, he wanted to give us his sacramental presence; since he was about to offer himself on the cross to save us, he wanted us to have the memorial of the love with which he loved us "to the end," [Jn 13:1] even to the giving of his life. In his Eucharistic presence he remains mysteriously in our midst as the one who loved us and gave himself up for us, [Cf. Gal 2:20] and he remains under signs that express and communicate this love: [669, 478]
The Church and the world have a great need for Eucharistic worship. Jesus awaits us in this sacrament of love. Let us not refuse the time to go to meet him in adoration, in contemplation full of faith, and open to making amends for the serious offenses and crimes of the world. Let our adoration never cease. [John Paul II, Dominicae cenae, 3] 
1381 "That in this sacrament are the true Body of Christ and his true Blood is something that 'cannot be apprehended by the senses,' says St. Thomas, 'but only by faith, which relies on divine authority.' For this reason, in a commentary on Luke 22:19 ('This is my body which is given for you.'), St. Cyril says: 'Do not doubt whether this is true, but rather receive the words of the Savior in faith, for since he is the truth, he cannot lie.'" [St. Thomas Aquinas, STh III, 75, 1; cf. Paul VI, MF 18; St. Cyril of Alexandria, In Luc. 22, 19: PG 72, 912; cf. Paul VI, MF 18.] [156, 215]
Godhead here in hiding, whom I do adore Masked by these bare shadows, shape and nothing more,
See, Lord, at thy service low lies here a heart Lost, all lost in wonder at the God thou art.
Seeing, touching, tasting are in thee deceived;
How says trusty hearing? that shall be believed;
What God's Son has told me, take for truth I do;
Truth himself speaks truly or there's nothing true. [St. Thomas Aquinas (attr.), Adoro te devote; tr. Gerard Manley Hopkins]
VI. THE PASCHAL BANQUET
1382 The Mass is at the same time, and inseparably, the sacrificial memorial in which the sacrifice of the cross is perpetuated and the sacred banquet of communion with the Lord's body and blood. But the celebration of the Eucharistic sacrifice is wholly directed toward the intimate union of the faithful with Christ through communion. To receive communion is to receive Christ himself who has offered himself for us. 
1383 The altar, around which the Church is gathered in the celebration of the Eucharist, represents the two aspects of the same mystery: the altar of the sacrifice and the table of the Lord. This is all the more so since the Christian altar is the symbol of Christ himself, present in the midst of the assembly of his faithful, both as the victim offered for our reconciliation and as food from heaven who is giving himself to us. "For what is the altar of Christ if not the image of the Body of Christ?" [St. Ambrose, De Sacr. 5, 2, 7: PL 16, 447C] asks St. Ambrose. He says elsewhere, "The altar represents the body [of Christ] and the Body of Christ is on the altar." [St. Ambrose, De Sacr. 4, 2, 7: PL 16, 437D] The liturgy expresses this unity of sacrifice and communion in many prayers. Thus the Roman Church prays in its anaphora: 
We entreat you, almighty God, that by the hands of your holy Angel this offering may be borne to your altar in heaven in the sight of your divine majesty, so that as we receive in communion at this altar the most holy Body and Blood of your Son, we may be filled with every heavenly blessing and grace. [Roman Missal, EP I (Roman Canon) 96: Supplices te rogamus, omnipotens Deus: iube haec perferri per manus sancti Angeli tui in sublime altare tuum, in conspectu divinae maiestatis tuae: ut, quotquot ex hac altaris participatione sacrosanctum Filii Corpus et Sanguinem sumpserimus, omni benedictione caelesti et gratia repleamur.]
"Take this and eat it, all of you": communion
1384 The Lord addresses an invitation to us, urging us to receive him in the sacrament of the Eucharist: "Truly, I say to you, unless you eat the flesh of the Son of man and drink his blood, you have no life in you." [Jn 6:53] 
1385 To respond to this invitation we must prepare ourselves for so great and so holy a moment. St. Paul urges us to examine our conscience: "Whoever, therefore, eats the bread or drinks the cup of the Lord in an unworthy manner will be guilty of profaning the body and blood of the Lord. Let a man examine himself, and so eat of the bread and drink of the cup. For any one who eats and drinks without discerning the body eats and drinks judgment upon himself." [1 Cor 11:27-29] Anyone conscious of a grave sin must receive the sacrament of Reconciliation before coming to communion. 
1386 Before so great a sacrament, the faithful can only echo humbly and with ardent faith the words of the Centurion: "Domine, non sum dignus ut intres sub tectum meum, sed tantum dic verbo, et sanabitur anima mea" ("Lord, I am not worthy that you should enter under my roof, but only say the word and my soul will be healed."). [Roman Missal, response to the invitation to communion; cf. Mt 8:8] And in the Divine Liturgy of St. John Chrysostom the faithful pray in the same spirit:
O Son of God, bring me into communion today with your mystical supper. I shall not tell your enemies the secret, nor kiss you with Judas' kiss. But like the good thief I cry, "Jesus, remember me when you come into your kingdom." 
1387 To prepare for worthy reception of this sacrament, the faithful should observe the fast required in their Church. [Cf. CIC, can. 919] Bodily demeanor (gestures, clothing) ought to convey the respect, solemnity, and joy of this moment when Christ becomes our guest. 
1388 It is in keeping with the very meaning of the Eucharist that the faithful, if they have the required dispositions, receive communion when they participate in the Mass. [Cf. CIC, can. 916] [Cf. CIC, can. 917; The faithful may receive the Holy Eucharist only a second time on the same day [Cf. Pontificia Commissio Codici luris Canonici Authentice Intrepretando, Responsa ad proposita dubia, 1:AAS 76 (1984) 746]] As the Second Vatican Council says: "That more perfect form of participation in the Mass whereby the faithful, after the priest's communion, receive the Lord's Body from the same sacrifice, is warmly recommended." [SC 55]
1389 The Church obliges the faithful to take part in the Divine Liturgy on Sundays and feast days and, prepared by the sacrament of Reconciliation, to receive the Eucharist at least once a year, if possible during the Easter season. [Cf OE 15; CIC, can. 920.] But the Church strongly encourages the faithful to receive the holy Eucharist on Sundays and feast days, or more often still, even daily. [2042, 2837]
1390 Since Christ is sacramentally present under each of the species, communion under the species of bread alone makes it possible to receive all the fruit of Eucharistic grace. For pastoral reasons this manner of receiving communion has been legitimately established as the most common form in the Latin rite. But "the sign of communion is more complete when given under both kinds, since in that form the sign of the Eucharistic meal appears more clearly." [GIRM 240] This is the usual form of receiving communion in the Eastern rites.
The fruits of Holy Communion
1391 Holy Communion augments our union with Christ. The principal fruit of receiving the Eucharist in Holy Communion is an intimate union with Christ Jesus. Indeed, the Lord said: "He who eats my flesh and drinks my blood abides in me, and I in him." [Jn 6:56] Life in Christ has its foundation in the Eucharistic banquet: "As the living Father sent me, and I live because of the Father, so he who eats me will live because of me." [Jn 6:57] [460, 521]
On the feasts of the Lord, when the faithful receive the Body of the Son, they proclaim to one another the Good News that the first fruits of life have been given, as when the angel said to Mary Magdalene, "Christ is risen!" Now too are life and resurrection conferred on whoever receives Christ. [Fanqith, Syriac Office of Antioch, Vol. 1, Commun., 237 a-b]
1392 What material food produces in our bodily life, Holy Communion wonderfully achieves in our spiritual life. Communion with the flesh of the risen Christ, a flesh "given life and giving life through the Holy Spirit," [PO 5] preserves, increases, and renews the life of grace received at Baptism. This growth in Christian life needs the nourishment of Eucharistic Communion, the bread for our pilgrimage until the moment of death, when it will be given to us as viaticum. [1200, 1524]
1393 Holy Communion separates us from sin. The body of Christ we receive in Holy Communion is "given up for us," and the blood we drink "shed for the many for the forgiveness of sins." For this reason the Eucharist cannot unite us to Christ without at the same time cleansing us from past sins and preserving us from future sins: 
For as often as we eat this bread and drink the cup, we proclaim the death of the Lord. If we proclaim the Lord's death, we proclaim the forgiveness of sins. If, as often as his blood is poured out, it is poured for the forgiveness of sins, I should always receive it, so that it may always forgive my sins. Because I always sin, I should always have a remedy. [St. Ambrose, De Sacr. 4, 6, 28: PL 16, 446; cf. 1 Cor 11:26]
1394 As bodily nourishment restores lost strength, so the Eucharist strengthens our charity, which tends to be weakened in daily life; and this living charity wipes away venial sins. [Cf. Council of Trent (1551): DS 1638] By giving himself to us Christ revives our love and enables us to break our disordered attachments to creatures and root ourselves in him: [1863, 1436]
Since Christ died for us out of love, when we celebrate the memorial of his death at the moment of sacrifice we ask that love may be granted to us by the coming of the Holy Spirit. We humbly pray that in the strength of this love by which Christ willed to die for us, we, by receiving the gift of the Holy Spirit, may be able to consider the world as crucified for us, and to be ourselves as crucified to the world.... Having received the gift of love, let us die to sin and live for God. [St. Fulgentius of Ruspe, Contra Fab. 28, 16-19: CCL 19A, 813-814]
1395 By the same charity that it enkindles in us, the Eucharist preserves us from future mortal sins. The more we share the life of Christ and progress in his friendship, the more difficult it is to break away from him by mortal sin. The Eucharist is not ordered to the forgiveness of mortal sins - that is proper to the sacrament of Reconciliation. The Eucharist is properly the sacrament of those who are in full communion with the Church. [1855, 1446]
1396 The unity of the Mystical Body: the Eucharist makes the Church. Those who receive the Eucharist are united more closely to Christ. Through it Christ unites them to all the faithful in one body - the Church. Communion renews, strengthens, and deepens this incorporation into the Church, already achieved by Baptism. In Baptism we have been called to form but one body. [Cf. 1 Cor 12:13] The Eucharist fulfills this call: "The cup of blessing which we bless, is it not a participation in the blood of Christ? The bread which we break, is it not a participation in the body of Christ? Because there is one bread, we who are many are one body, for we all partake of the one bread:" [1 Cor 10:16-17] [1118, 1267, 790]
If you are the body and members of Christ, then it is your sacrament that is placed on the table of the Lord; it is your sacrament that you receive. To that which you are you respond "Amen" ("yes, it is true!") and by responding to it you assent to it. For you hear the words, "the Body of Christ" and respond "Amen." Be then a member of the Body of Christ that your Amen may be true. [St. Augustine, Sermo 272: PL 38, 1247] 
1397 The Eucharist commits us to the poor. To receive in truth the Body and Blood of Christ given up for us, we must recognize Christ in the poorest, his brethren: 
You have tasted the Blood of the Lord, yet you do not recognize your brother,.... You dishonor this table when you do not judge worthy of sharing your food someone judged worthy to take part in this meal.... God freed you from all your sins and invited you here, but you have not become more merciful. [St. John Chrysostom, Hom. in 1 Cor. 27, 4: PG 61, 229-230; cf. Mt 25:40]
1398 The Eucharist and the unity of Christians. Before the greatness of this mystery St. Augustine exclaims, "O sacrament of devotion! O sign of unity! O bond of charity!" [St. Augustine, In Jo. ev. 26, 13: PL 35, 1613; cf. SC 47] The more painful the experience of the divisions in the Church which break the common participation in the table of the Lord, the more urgent are our prayers to the Lord that the time of complete unity among all who believe in him may return. 
1399 The Eastern churches that are not in full communion with the Catholic Church celebrate the Eucharist with great love. "These Churches, although separated from us, yet possess true sacraments, above all - by apostolic succession - the priesthood and the Eucharist, whereby they are still joined to us in closest intimacy." A certain communion in sacris, and so in the Eucharist, "given suitable circumstances and the approval of Church authority, is not merely possible but is encouraged." [UR 15 § 2; cf. CIC, can. 844 § 3.] 
1400 Ecclesial communities derived from the Reformation and separated from the Catholic Church, "have not preserved the proper reality of the Eucharistic mystery in its fullness, especially because of the absence of the sacrament of Holy Orders." [UR 22 § 3] It is for this reason that, for the Catholic Church, Eucharistic intercommunion with these communities is not possible. However these ecclesial communities, "when they commemorate the Lord's death and resurrection in the Holy Supper... profess that it signifies life in communion with Christ and await his coming in glory." [UR 22 § 3] 
1401 When, in the Ordinary's judgment, a grave necessity arises, Catholic ministers may give the sacraments of Eucharist, Penance, and Anointing of the Sick to other Christians not in full communion with the Catholic Church, who ask for them of their own will, provided they give evidence of holding the Catholic faith regarding these sacraments and possess the required dispositions. [Cf. CIC, can. 844 § 4] [1483, 1385]
VII. THE EUCHARIST - "PLEDGE OF THE GLORY TO COME"
1402 In an ancient prayer the Church acclaims the mystery of the Eucharist: "O sacred banquet in which Christ is received as food, the memory of his Passion is renewed, the soul is filled with grace and a pledge of the life to come is given to us." If the Eucharist is the memorial of the Passover of the Lord Jesus, if by our communion at the altar we are filled "with every heavenly blessing and grace," [Roman Missal, EP I (Roman Canon) 96: Supplices te rogamus] then the Eucharist is also an anticipation of the heavenly glory. [1323, 1130]
1403 At the Last Supper the Lord himself directed his disciples' attention toward the fulfillment of the Passover in the kingdom of God: "I tell you I shall not drink again of this fruit of the vine until that day when I drink it new with you in my Father's kingdom." [Mt 26:29; cf. Lk 22:18; Mk 14:25] Whenever the Church celebrates the Eucharist she remembers this promise and turns her gaze "to him who is to come." In her prayer she calls for his coming: "Marana tha!" "Come, Lord Jesus!" [Rev 1:4; 22 20; 1 Cor 16 22] "May your grace come and this world pass away!" [Didache 10, 6: SCh 248,180] 
1404 The Church knows that the Lord comes even now in his Eucharist and that he is there in our midst. However, his presence is veiled. Therefore we celebrate the Eucharist "awaiting the blessed hope and the coming of our Savior, Jesus Christ," [Roman Missal 126, embolism after the Our Father: expectantes beatam spem et adventum Salvatoris nostri Jesu Christi; cf. Titus 2:13.] asking "to share in your glory when every tear will be wiped away. On that day we shall see you, our God, as you are. We shall become like you and praise you for ever through Christ our Lord." [EP III 116: prayer for the dead] [1041, 1028]
1405 There is no surer pledge or dearer sign of this great hope in the new heavens and new earth "in which righteousness dwells," [2 Pet 3:13] than the Eucharist. Every time this mystery is celebrated, "the work of our redemption is carried on" and we "break the one bread that provides the medicine of immortality, the antidote for death, and the food that makes us live for ever in Jesus Christ." [LG 3; St. Ignatius of Antioch, Ad Eph. 20, 2: SCh 10, 76] [1042, 1000]
1406 Jesus said: "I am the living bread that came down from heaven; if any one eats of this bread, he will live for ever;... he who eats my flesh and drinks my blood has eternal life and... abides in me, and I in him" (Jn 6:51, 54, 56).
1407 The Eucharist is the heart and the summit of the Church's life, for in it Christ associates his Church and all her members with his sacrifice of praise and thanksgiving offered once for all on the cross to his Father; by this sacrifice he pours out the graces of salvation on his Body which is the Church.
1408 The Eucharistic celebration always includes: the proclamation of the Word of God; thanksgiving to God the Father for all his benefits, above all the gift of his Son; the consecration of bread and wine; and participation in the liturgical banquet by receiving the Lord's body and blood. These elements constitute one single act of worship.
1409 The Eucharist is the memorial of Christ's Passover, that is, of the work of salvation accomplished by the life, death, and resurrection of Christ, a work made present by the liturgical action.
1410 It is Christ himself, the eternal high priest of the New Covenant who, acting through the ministry of the priests, offers the Eucharistic sacrifice. And it is the same Christ, really present under the species of bread and wine, who is the offering of the Eucharistic sacrifice.
1411 Only validly ordained priests can preside at the Eucharist and consecrate the bread and the wine so that they become the Body and Blood of the Lord.
1412 The essential signs of the Eucharistic sacrament are wheat bread and grape wine, on which the blessing of the Holy Spirit is invoked and the priest pronounces the words of consecration spoken by Jesus during the Last Supper: "This is my body which will be given up for you.... This is the cup of my blood...."
1413 By the consecration the transubstantiation of the bread and wine into the Body and Blood of Christ is brought about. Under the consecrated species of bread and wine Christ himself, living and glorious, is present in a true, real, and substantial manner: his Body and his Blood, with his soul and his divinity (cf. Council of Trent: DS 1640; 1651).
1414 As sacrifice, the Eucharist is also offered in reparation for the sins of the living and the dead and to obtain spiritual or temporal benefits from God.
1415 Anyone who desires to receive Christ in Eucharistic communion must be in the state of grace. Anyone aware of having sinned mortally must not receive communion without having received absolution in the sacrament of penance.
1416 Communion with the Body and Blood of Christ increases the communicant's union with the Lord, forgives his venial sins, and preserves him from grave sins. Since receiving this sacrament strengthens the bonds of charity between the communicant and Christ, it also reinforces the unity of the Church as the Mystical Body of Christ.
1417 The Church warmly recommends that the faithful receive Holy Communion when they participate in the celebration of the Eucharist; she obliges them to do so at least once a year.
1418 Because Christ himself is present in the sacrament of the altar, he is to be honored with the worship of adoration. "To visit the Blessed Sacrament is... a proof of gratitude, an expression of love, and a duty of adoration toward Christ our Lord" (Paul VI, MF 66).
1419 Having passed from this world to the Father, Christ gives us in the Eucharist the pledge of glory with him. Participation in the Holy Sacrifice identifies us with his Heart, sustains our strength along the pilgrimage of this life, makes us long for eternal life, and unites us even now to the Church in heaven, the Blessed Virgin Mary, and all the saints.