I. THE CREEDS
185 Whoever says "I believe" says "I pledge myself to what we believe." Communion in faith needs a common language of faith, normative for all and uniting all in the same confession of faith. [171, 949]
186 From the beginning, the apostolic Church expressed and handed on her faith in brief formulae normative for all. [Cf. Rom 10:9; 1 Cor 15:3-5, etc.] But already very early on, the Church also wanted to gather the essential elements of her faith into organic and articulated summaries, intended especially for candidates for Baptism:
This synthesis of faith was not made to accord with human opinions, but rather what was of the greatest importance was gathered from all the Scriptures, to present the one teaching of the faith in its entirety. And just as the mustard seed contains a great number of branches in a tiny grain, so too this summary of faith encompassed in a few words the whole knowledge of the true religion contained in the Old and the New Testaments. [St. Cyril of Jerusalem, Catech. illum. 5, 12: PG 33, 521-524.]
187 Such syntheses are called "professions of faith" since they summarize the faith that Christians profess. They are called "creeds" on account of what is usually their first word in Latin: credo ("I believe"). They are also called "symbols of faith".
188 The Greek word symbolon meant half of a broken object, for example, a seal presented as a token of recognition. The broken parts were placed together to verify the bearer's identity. The symbol of faith, then, is a sign of recognition and communion between believers. Symbolon also means a gathering, collection or summary. A symbol of faith is a summary of the principal truths of the faith and therefore serves as the first and fundamental point of reference for catechesis.
189 The first "profession of faith" is made during Baptism. The symbol of faith is first and foremost the baptismal creed. Since Baptism is given "in the name of the Father and of the Son and of the Holy Spirit", [Mt 28:19.] the truths of faith professed during Baptism are articulated in terms of their reference to the three persons of the Holy Trinity. [1237, 232]
190 And so the Creed is divided into three parts: "the first part speaks of the first divine Person and the wonderful work of creation; the next speaks of the second divine Person and the mystery of his redemption of men; the final part speaks of the third divine Person, the origin and source of our sanctification." [Roman Catechism I, 1, 3.] These are "the three chapters of our [baptismal] seal". [St. Irenaeus, Dem. ap. 100: SCh 62, 170.]
191 "These three parts are distinct although connected with one another. According to a comparison often used by the Fathers, we call them articles. Indeed, just as in our bodily members there are certain articulations which distinguish and separate them, so too in this profession of faith, the name articles has justly and rightly been given to the truths we must believe particularly and distinctly." [Roman Catechism I, I, 4.] In accordance with an ancient tradition, already attested to by St. Ambrose, it is also customary to reckon the articles of the Creed as twelve, thus symbolizing the fullness of the apostolic faith by the number of the apostles. [Cf. St. Ambrose, Expl. symb. 8: PL 17, 1196.]
192 Through the centuries many professions or symbols of faith have been articulated in response to the needs of the different eras: the creeds of the different apostolic and ancient Churches, [Cf. DS 1-64.] e.g., the Quicumque, also called the Athanasian Creed; [Cf. DS 75-76.] the professions of faith of certain Councils, such as Toledo, Lateran, Lyons, Trent; [Cf. DS 525-541; 800-802; 851-861; 1862-1870.] or the symbols of certain popes, e.g., the Fides Damasi [Cf. DS 71-72.] or the Credo of the People of God of Paul VI. [Paul VI, CPG (1968).]
193 None of the creeds from the different stages in the Church's life can be considered superseded or irrelevant. They help us today to attain and deepen the faith of all times by means of the different summaries made of it.
Among all the creeds, two occupy a special place in the Church's life:
194 The Apostles' Creed is so called because it is rightly considered to be a faithful summary of the apostles' faith. It is the ancient baptismal symbol of the Church of Rome. Its great authority arises from this fact: it is "the Creed of the Roman Church, the See of Peter the first of the apostles, to which he brought the common faith". [St. Ambrose, Expl. symb. 7: PL 17, 1196.]
195 The Niceno-Constantinopolitan or Nicene Creed draws its great authority from the fact that it stems from the first two ecumenical Councils (in 325 and 381). It remains common to all the great Churches of both East and West to this day. [242, 245, 465]
196 Our presentation of the faith will follow the Apostles' Creed, which constitutes, as it were, "the oldest Roman catechism". The presentation will be completed however by constant references to the Nicene Creed, which is often more explicit and more detailed.
197 As on the day of our Baptism, when our whole life was entrusted to the "standard of teaching", [Rom 6:17.] let us embrace the Creed of our life-giving faith. To say the Credo with faith is to enter into communion with God, Father, Son and Holy Spirit, and also with the whole Church which transmits the faith to us and in whose midst we believe: 
This Creed is the spiritual seal, our heart's meditation and an ever-present guardian; it is, unquestionably, the treasure of our soul. [St. Ambrose, Expl. symb. I: PL 17, 1193.] 
I BELIEVE IN GOD THE FATHER
198 Our profession of faith begins with God, for God is the First and the Last, [Cf. Is 44:6.] the beginning and the end of everything. The Credo begins with God the Father, for the Father is the first divine person of the Most Holy Trinity; our Creed begins with the creation of heaven and earth, for creation is the beginning and the foundation of all God's works.
"I BELIEVE IN GOD THE FATHER ALMIGHTY, CREATOR OF HEAVEN AND EARTH"
Paragraph I. I Believe in God
199 "I believe in God": this first affirmation of the Apostles' Creed is also the most fundamental. The whole Creed speaks of God, and when it also speaks of man and of the world it does so in relation to God. The other articles of the Creed all depend on the first, just as the remaining Commandments make the first explicit. The other articles help us to know God better as he revealed himself progressively to men. "The faithful first profess their belief in God." [Roman Catechism I, 2, 2.] 
I. "I BELIEVE IN ONE GOD"
200 These are the words with which the Niceno- Constantinopolitan Creed begins. The confession of God's oneness, which has its roots in the divine revelation of the Old Covenant, is inseparable from the profession of God's existence and is equally fundamental. God is unique; there is only one God: "The Christian faith confesses that God is one in nature, substance and essence." [Roman Catechism I, 2, 2.] 
201 To Israel, his chosen, God revealed himself as the only One: "Hear, O Israel: The LORD our God is one LORD; and you shall love the LORD your God with all your heart, and with all your soul, and with all your might." [Dt 6:45.] Through the prophets, God calls Israel and all nations to turn to him, the one and only God: "Turn to me and be saved, all the ends of the earth! For I am God, and there is no other.. . To me every knee shall bow, every tongue shall swear. 'Only in the LORD, it shall be said of me, are righteousness and strength.'" [Is 45:22-24; cf. Phil 2:10-11.] 
202 Jesus himself affirms that God is "the one Lord" whom you must love "with all your heart, and with all your soul, and with all your mind, and with all your strength". [Mk 12:29-30] At the same time Jesus gives us to understand that he himself is "the Lord". [Cf. Mk 12:35-37.] To confess that Jesus is Lord is distinctive of Christian faith. This is not contrary to belief in the One God. Nor does believing in the Holy Spirit as "Lord and giver of life" introduce any division into the One God: [446, 152]
We firmly believe and confess without reservation that there is only one true God, eternal infinite (immensus) and unchangeable, incomprehensible, almighty and ineffable, the Father and the Son and the Holy Spirit; three persons indeed, but one essence, substance or nature entirely simple. [Lateran Council IV: DS 800.] 
II. GOD REVEALS HIS NAME
203 God revealed himself to his people Israel by making his name known to them. A name expresses a person's essence and identity and the meaning of this person's life. God has a name; he is not an anonymous force. To disclose one's name is to make oneself known to others; in a way it is to hand oneself over by becoming accessible, capable of being known more intimately and addressed personally. 
204 God revealed himself progressively and under different names to his people, but the revelation that proved to be the fundamental one for both the Old and the New Covenants was the revelation of the divine name to Moses in the theophany of the burning bush, on the threshold of the Exodus and of the covenant on Sinai. 
The living God
205 God calls Moses from the midst of a bush that bums without being consumed: "I am the God of your father, the God of Abraham, the God of Isaac, and the God of Jacob." [Ex 3:6.] God is the God of the fathers, the One who had called and guided the patriarchs in their wanderings. He is the faithful and compassionate God who remembers them and his promises; he comes to free their descendants from slavery. He is the God who, from beyond space and time, can do this and wills to do it, the God who will put his almighty power to work for this plan. [2575, 268]
"I AM WHO I AM."
Moses said to God, "If I come to the people of Israel and say to them, 'The God of your fathers has sent me to you', and they ask me, 'What is his name?' what shall I say to them?" God said to Moses, And he said, "Say this to the people of Israel, 'I AM has sent me to you'... this is my name for ever, and thus I am to be remembered throughout all generations." [Ex 3:13-15.]
206 In revealing his mysterious name, YHWH ("I AM HE WHO IS", "I AM WHO AM" or "I AM WHO I AM"), God says who he is and by what name he is to be called. This divine name is mysterious just as God is mystery. It is at once a name revealed and something like the refusal of a name, and hence it better expresses God as what he is - infinitely above everything that we can understand or say: he is the "hidden God", his name is ineffable, and he is the God who makes himself close to men. [Cf. Is 45:15; Judg 13:18.]
207 By revealing his name God at the same time reveals his faithfulness which is from everlasting to everlasting, valid for the past ("I am the God of your father"), as for the future ("I will be with you"). [Ex 3:6, 12.] God, who reveals his name as "I AM", reveals himself as the God who is always there, present to his people in order to save them.
208 Faced with God's fascinating and mysterious presence, man discovers his own insignificance. Before the burning bush, Moses takes off his sandals and veils his face in the presence of God's holiness. [Cf. Ex 3:5-6.] Before the glory of the thrice-holy God, Isaiah cries out: "Woe is me! I am lost; for I am a man of unclean lips." [Is 6:5.] Before the divine signs wrought by Jesus, Peter exclaims: "Depart from me, for I am a sinful man, O Lord." [Lk 5:8.] But because God is holy, he can forgive the man who realizes that he is a sinner before him: "I will not execute my fierce anger... for I am God and not man, the Holy One in your midst." [Hos 11:9.] The apostle John says likewise: "We shall... reassure our hearts before him whenever our hearts condemn us; for God is greater than our hearts, and he knows everything." [1 Jn 3:19-20.] [724, 448, 388]
209 Out of respect for the holiness of God, the people of Israel do not pronounce his name. In the reading of Sacred Scripture, the revealed name (YHWH) is replaced by the divine title "LORD" (in Hebrew Adonai, in Greek Kyrios). It is under this title that the divinity of Jesus will be acclaimed: "Jesus is LORD." 
"A God merciful and gracious"
210 After Israel's sin, when the people had turned away from God to worship the golden calf, God hears Moses' prayer of intercession and agrees to walk in the midst of an unfaithful people, thus demonstrating his love. [Cf. Ex 32; 33: 12-17.] When Moses asks to see his glory, God responds "I will make all my goodness pass before you, and will proclaim before you my name "the LORD" [YHWH]." [Ex 33:18-19.] Then the LORD passes before Moses and proclaims, "YHWH, YHWH, a God merciful and gracious, slow to anger, and abounding in steadfast love and faithfulness"; Moses then confesses that the LORD is a forgiving God. [Ex 34:5-6; cf. 34:9.] [2116, 2577]
211 The divine name, "I Am" or "He Is", expresses God's faithfulness: despite the faithlessness of men's sin and the punishment it deserves, he keeps "steadfast love for thousands". [Ex 34:7.] By going so far as to give up his own Son for us, God reveals that he is "rich in mercy". [Eph 2:4.] By giving his life to free us from sin, Jesus reveals that he himself bears the divine name: "When you have lifted up the Son of man, then you will realize that "I AM"." [Jn 8:28 (Greek).] 
God alone IS
212 Over the centuries, Israel's faith was able to manifest and deepen realization of the riches contained in the revelation of the divine name. God is unique; there are no other gods besides him. [Cf. Is 44:6.] He transcends the world and history. He made heaven and earth: "They will perish, but you endure; they will all wear out like a garment....but you are the same, and your years have no end." [Ps 102:26-27.] In God "there is no variation or shadow due to change." [Jas 1:17.] God is "HE WHO IS", from everlasting to everlasting, and as such remains ever faithful to himself and to his promises. [42, 469, 2086]
213 The revelation of the ineffable name "I AM WHO AM" contains then the truth that God alone IS. The Greek Septuagint translation of the Hebrew Scriptures, and following it the Church's Tradition, understood the divine name in this sense: God is the fullness of Being and of every perfection, without origin and without end. All creatures receive all that they are and have from him; but he alone is his very being, and he is of himself everything that he is. 
III. GOD, "HE WHO IS", IS TRUTH AND LOVE
214 God, "HE WHO IS", revealed himself to Israel as the one "abounding in steadfast love and faithfulness". [Ex 34:6.] These two terms express summarily the riches of the divine name. In all his works God displays, not only his kindness, goodness, grace and steadfast love, but also his trustworthiness, constancy, faithfulness and truth. "I give thanks to your name for your steadfast love and your faithfulness." [Ps 138:2; cf. Ps 85:11.] He is the Truth, for "God is light and in him there is no darkness"; "God is love", as the apostle John teaches. [1 Jn 1:5; 4:8.] 
God is Truth
215 "The sum of your word is truth; and every one of your righteous ordinances endures forever." [Ps 119:160.] "And now, O LORD God, you are God, and your words are true"; [2 Sam 7:28.] this is why God's promises always come true. [Cf. Dt 7:9.] God is Truth itself, whose words cannot deceive. This is why one can abandon oneself in full trust to the truth and faithfulness of his word in all things. The beginning of sin and of man's fall was due to a lie of the tempter who induced doubt of God's word, kindness and faithfulness. [2465, 1063, 156, 397]
216 God's truth is his wisdom, which commands the whole created order and governs the world. [Cf Wis 13:1-9.] God, who alone made heaven and earth, can alone impart true knowledge of every created thing in relation to himself. [Cf Ps 115:15; Wis 7:17-21.] [295, 32]
217 God is also truthful when he reveals himself - the teaching that comes from God is "true instruction". [Mal 2:6.] When he sends his Son into the world it will be "to bear witness to the truth": [Jn 18:37.] "We know that the Son of God has come and has given us understanding, to know him who is true." [1 Jn 5:20; cf. Jn 17:3.] [851, 2466]
God is Love
218 In the course of its history, Israel was able to discover that God had only one reason to reveal himself to them, a single motive for choosing them from among all peoples as his special possession: his sheer gratuitous love. [Cf. Dt 4:37; 7:8; 10:15.] And thanks to the prophets Israel understood that it was again out of love that God never stopped saving them and pardoning their unfaithfulness and sins. [Cf. Is 43:1-7; Hos 2.] 
219 God's love for Israel is compared to a father's love for his son. His love for his people is stronger than a mother's for her children. God loves his people more than a bridegroom his beloved; his love will be victorious over even the worst infidelities and will extend to his most precious gift: "God so loved the world that he gave his only Son." [Jn 3:16; cf. Hos 11:1; Is 49:14-15; 62 :4-5; Ezek 16; Hos 11.] [239, 796, 458]
220 God's love is "everlasting": [Is 54:8.] "For the mountains may depart and the hills be removed, but my steadfast love shall not depart from you." [Is 54: 10; cf. 54:8.] Through Jeremiah, God declares to his people, "I have loved you with an everlasting love; therefore I have continued my faithfulness to you." [Jer 31:3.]
221 But St. John goes even further when he affirms that "God is love": [l Jn 4:8, 16.] God's very being is love. By sending his only Son and the Spirit of Love in the fullness of time, God has revealed his innermost secret: [Cf. 1 Cor 2:7-16; Eph 3:9-12.] God himself is an eternal exchange of love, Father, Son and Holy Spirit, and he has destined us to share in that exchange. [733, 851, 257]
IV. THE IMPLICATIONS OF FAITH IN ONE GOD
222 Believing in God, the only One, and loving him with all our being has enormous consequences for our whole life.
223 It means coming to know God's greatness and majesty: "Behold, God is great, and we know him not." [Job 36:26.] Therefore, we must "serve God first". [St. Joan of Arc.] 
224 It means living in thanksgiving: if God is the only One, everything we are and have comes from him: "What have you that you did not receive?" [1 Cor 4:7.] "What shall I render to the LORD for all his bounty to me?" [Ps 116:12.] 
225 It means knowing the unity and true dignity of all men: everyone is made in the image and likeness of God. [Gen 1:26.] [256, 360, 1700, 1934]
226 It means making good use of created things: faith in God, the only One, leads us to use everything that is not God only insofar as it brings us closer to him, and to detach ourselves from it insofar as it turns us away from him: [339, 2402, 2415]
My Lord and my God, take from me everything that distances me from you.
My Lord and my God, give me everything that brings me closer to you. My Lord and my God, detach me from myself to give my all to you. [St. Nicholas of Flue; cf. Mt 5:29-30; 16:24-26.]
227 It means trusting God in every circumstance, even in adversity. A prayer of St. Teresa of Jesus wonderfully expresses this trust: [313, 2090]
Let nothing trouble you / Let nothing frighten you
Everything passes / God never changes
Patience / Obtains all
Whoever has God / Wants for nothing
God alone is enough. [St. Teresa of Jesus, Poesias 30 in The Collected Works of St. Teresa of Avila, vol. III, tr. K. Kavanaugh OCD and O. Rodriguez OCD (Washington DC Institute of Carmelite Studies, 1985), 386 no. 9. tr. John Wall.] [2830, 1723]
228 "Hear, O Israel, the LORD our God is one LORD..." (Dt 6:4; Mk 12:29). "The supreme being must be unique, without equal... If God is not one, he is not God" (Tertullian, Adv. Marc., 1, 3, 5: PL 2, 274).
229 Faith in God leads us to turn to him alone as our first origin and our ultimate goal, and neither to prefer anything to him nor to substitute anything for him.
230 Even when he reveals himself, God remains a mystery beyond words: "If you understood him, it would not be God" (St. Augustine, Sermo 52, 6, 16: PL 38, 360 and Sermo 117, 3, 5: PL 38, 663).
231 The God of our faith has revealed himself as HE WHO IS; and he has made himself known as "abounding in steadfast love and faithfulness" (Ex 34:6). God's very being is Truth and Love.
Paragraph 2. The Father
I. "IN THE NAME OF THE FATHER AND OF THE SON AND OF THE HOLY SPIRIT"
232 Christians are baptized "in the name of the Father and of the Son and of the Holy Spirit" [Mt 28:19.] Before receiving the sacrament, they respond to a three-part question when asked to confess the Father, the Son and the Spirit: "I do." "The faith of all Christians rests on the Trinity." [St. Caesarius of Arles, Sermo 9, Exp. symb.: CCL 103, 47.] [189, 1223]
233 Christians are baptized in the name of the Father and of the Son and of the Holy Spirit: not in their names, [Cf. Profession of faith of Pope Vigilius I (552): DS 415.] for there is only one God, the almighty Father, his only Son and the Holy Spirit: the Most Holy Trinity.
234 The mystery of the Most Holy Trinity is the central mystery of Christian faith and life. It is the mystery of God in himself. It is therefore the source of all the other mysteries of faith, the light that enlightens them. It is the most fundamental and essential teaching in the "hierarchy of the truths of faith". [GCD 43.] The whole history of salvation is identical with the history of the way and the means by which the one true God, Father, Son and Holy Spirit, reveals himself to men "and reconciles and unites with himself those who turn away from sin". [GCD 47.] [2157, 90, 1449]
235 This paragraph expounds briefly (I) how the mystery of the Blessed Trinity was revealed, (II) how the Church has articulated the doctrine of the faith regarding this mystery, and (III) how, by the divine missions of the Son and the Holy Spirit, God the Father fulfils the "plan of his loving goodness" of creation, redemption and sanctification.
236 The Fathers of the Church distinguish between theology (theologia) and economy (oikonomia). "Theology" refers to the mystery of God's inmost life within the Blessed Trinity and "economy" to all the works by which God reveals himself and communicates his life. Through the oikonomia the theologia is revealed to us; but conversely, the theologia illuminates the whole oikonomia. God's works reveal who he is in himself; the mystery of his inmost being enlightens our understanding of all his works. So it is, analogously, among human persons. A person discloses himself in his actions, and the better we know a person, the better we understand his actions. [1066, 259]
237 The Trinity is a mystery of faith in the strict sense, one of the "mysteries that are hidden in God, which can never be known unless they are revealed by God". [Dei Filius 4: DS 3015.] To be sure, God has left traces of his Trinitarian being in his work of creation and in his Revelation throughout the Old Testament. But his inmost Being as Holy Trinity is a mystery that is inaccessible to reason alone or even to Israel's faith before the Incarnation of God's Son and the sending of the Holy Spirit. 
II. THE REVELATION OF GOD AS TRINITY
The Father revealed by the Son
238 Many religions invoke God as "Father". The deity is often considered the "father of gods and of men". In Israel, God is called "Father" inasmuch as he is Creator of the world. [Cf. Dt 32:6; Mal 2:10.] Even more, God is Father because of the covenant and the gift of the law to Israel, "his first-born son". [Ex 4:22.] God is also called the Father of the king of Israel. Most especially he is "the Father of the poor", of the orphaned and the widowed, who are under his loving protection. [Cf. 2 Sam 7:14; Ps 68:6.] 
239 By calling God "Father", the language of faith indicates two main things: that God is the first origin of everything and transcendent authority; and that he is at the same time goodness and loving care for all his children. God's parental tenderness can also be expressed by the image of motherhood, [Cf. Is 66:13; Ps 131:2.] which emphasizes God's immanence, the intimacy between Creator and creature. The language of faith thus draws on the human experience of parents, who are in a way the first representatives of God for man. But this experience also tells us that human parents are fallible and can disfigure the face of fatherhood and motherhood. We ought therefore to recall that God transcends the human distinction between the sexes. He is neither man nor woman: he is God. He also transcends human fatherhood and motherhood, although he is their origin and standard: [Cf. Ps 27:10; Eph 3:14; Is 49:15.] no one is father as God is Father. [370, 2779]
240 "Jesus revealed that God is Father in an unheard-of sense: he is Father not only in being Creator; he is eternally Father in relation to his only Son, who is eternally Son only in relation to his Father: "No one knows the Son except the Father, and no one knows the Father except the Son and anyone to whom the Son chooses to reveal him." [Mt. 11-27.] [2780, 441-445]
241 For this reason the apostles confess Jesus to be the Word: "In the beginning was the Word, and the Word was with God, and the Word was God"; as "the image of the invisible God"; as the "radiance of the glory of God and the very stamp of his nature". [Jn 1:1; Col 1:15; Heb 1:3.]
242 Following this apostolic tradition, the Church confessed at the first ecumenical council at Nicaea (325) that the Son is "consubstantial" with the Father, that is, one only God with him. [The English phrases "of one being" and "one in being" translate the Greek word homoousios, which was rendered in Latin by consubstantialis.] The second ecumenical council, held at Constantinople in 381, kept this expression in its formulation of the Nicene Creed and confessed "the only- begotten Son of God, eternally begotten of the Father, light from light, true God from true God, begotten not made, consubstantial with the Father". [Niceno-Constantinopolitan Creed; cf. DS 150.] 
The Father and the son revealed by the spirit
243 Before his Passover, Jesus announced the sending of "another Paraclete" (Advocate), the Holy Spirit. At work since creation, having previously "spoken through the prophets", the Spirit will now be with and in the disciples, to teach them and guide them "into all the truth". [Cf. Gen 1:2; Nicene Creed (DS 150); Jn 14:17, 26; 16:13.] The Holy Spirit is thus revealed as another divine person with Jesus and the Father. [683, 2780, 687]
244 The eternal origin of the Holy Spirit is revealed in his mission in time. The Spirit is sent to the apostles and to the Church both by the Father in the name of the Son, and by the Son in person, once he had returned to the Father. [Cf. Jn 14:26; 15:26; 16:14.] The sending of the person of the Spirit after Jesus' glorification [Cf. Jn 7:39.] reveals in its fullness the mystery of the Holy Trinity. 
245 The apostolic faith concerning the Spirit was confessed by the second ecumenical council at Constantinople (381): "We believe in the Holy Spirit, the Lord and giver of life, who proceeds from the Father." [Nicene Creed; cf. DS 150.] By this confession, the Church recognizes the Father as "the source and origin of the whole divinity". [Council of Toledo VI (638): DS 490.] But the eternal origin of the Spirit is not unconnected with the Son's origin: "The Holy Spirit, the third person of the Trinity, is God, one and equal with the Father and the Son, of the same substance and also of the same nature... Yet he is not called the Spirit of the Father alone,... but the Spirit of both the Father and the Son." [Council of Toledo XI (675): DS 527.] The Creed of the Church from the Council of Constantinople confesses: "With the Father and the Son, he is worshipped and glorified." [Nicene Creed; cf. DS 150.] [152, 685]
246 The Latin tradition of the Creed confesses that the Spirit "proceeds from the Father and the Son (filioque)". The Council of Florence in 1438 explains: "The Holy Spirit is eternally from Father and Son; He has his nature and subsistence at once (simul) from the Father and the Son. He proceeds eternally from both as from one principle and through one spiration... And, since the Father has through generation given to the only-begotten Son everything that belongs to the Father, except being Father, the Son has also eternally from the Father, from whom he is eternally born, that the Holy Spirit proceeds from the Son." [Council of Florence (1439): DS 1300-1301.]
247 The affirmation of the filioque does not appear in the Creed confessed in 381 at Constantinople. But Pope St. Leo I, following an ancient Latin and Alexandrian tradition, had already confessed it dogmatically in 447, [Cf. Leo I, Quam laudabiliter (447): DS 284.] even before Rome, in 451 at the Council of Chalcedon, came to recognize and receive the Symbol of 381. The use of this formula in the Creed was gradually admitted into the Latin liturgy (between the eighth and eleventh centuries). The introduction of the filioque into the Niceno-Constantinopolitan Creed by the Latin liturgy constitutes moreover, even today, a point of disagreement with the Orthodox Churches.
248 At the outset the Eastern tradition expresses the Father's character as first origin of the Spirit. By confessing the Spirit as he "who proceeds from the Father", it affirms that he comes from the Father through the Son. [Jn 15:26; cf. AG 2.] The Western tradition expresses first the consubstantial communion between Father and Son, by saying that the Spirit proceeds from the Father and the Son (filioque). It says this, "legitimately and with good reason", [Council of Florence (1439): DS 1302.] for the eternal order of the divine persons in their consubstantial communion implies that the Father, as "the principle without principle", [Council of Florence (1442): DS 1331.] is the first origin of the Spirit, but also that as Father of the only Son, he is, with the Son, the single principle from which the Holy Spirit proceeds. [Cf. Council of Lyons II(1274): DS 850.] This legitimate complementarity, provided it does not become rigid, does not affect the identity of faith in the reality of the same mystery confessed.
III. THE HOLY TRINITY IN THE TEACHING OF THE FAITH
The formation of the Trinitarian dogma
249 From the beginning, the revealed truth of the Holy Trinity has been at the very root of the Church's living faith, principally by means of Baptism. It finds its expression in the rule of baptismal faith, formulated in the preaching, catechesis and prayer of the Church. Such formulations are already found in the apostolic writings, such as this salutation taken up in the Eucharistic liturgy: "The grace of the Lord Jesus Christ and the love of God and the fellowship of the Holy Spirit be with you all." [2 Cor 13:14; cf. I Cor 12:4 - 6; Eph 4:4-6.] [683, 189]
250 During the first centuries the Church sought to clarify her Trinitarian faith, both to deepen her own understanding of the faith and to defend it against the errors that were deforming it. This clarification was the work of the early councils, aided by the theological work of the Church Fathers and sustained by the Christian people's sense of the faith. 
251 In order to articulate the dogma of the Trinity, the Church had to develop her own terminology with the help of certain notions of philosophical origin: "substance", "person" or "hypostasis", "relation" and so on. In doing this, she did not submit the faith to human wisdom, but gave a new and unprecedented meaning to these terms, which from then on would be used to signify an ineffable mystery, "infinitely beyond all that we can humanly understand". [Paul VI, CPC # 2.] 
252 The Church uses (I) the term "substance" (rendered also at times by "essence" or "nature") to designate the divine being in its unity, (II) the term "person" or "hypostasis" to designate the Father, Son and Holy Spirit in the real distinction among them, and (III) the term "relation" to designate the fact that their distinction lies in the relationship of each to the others.
The dogma of the Holy Trinity
253 The Trinity is One. We do not confess three Gods, but one God in three persons, the "consubstantial Trinity". [Council of Constantinople II (553): DS 421.] The divine persons do not share the one divinity among themselves but each of them is God whole and entire: "The Father is that which the Son is, the Son that which the Father is, the Father and the Son that which the Holy Spirit is, i.e. by nature one God." [Council of Toledo XI (675): DS 530:26.] In the words of the Fourth Lateran Council (1215), "Each of the persons is that supreme reality, viz., the divine substance, essence or nature." [Lateran Council IV (1215): DS 804.] [2789, 590]
254 The divine persons are really distinct from one another. "God is one but not solitary." [Fides Damasi: DS 71.] "Father", "Son", "Holy Spirit" are not simply names designating modalities of the divine being, for they are really distinct from one another: "He is not the Father who is the Son, nor is the Son he who is the Father, nor is the Holy Spirit he who is the Father or the Son." [Council of Toledo XI (675): DS 530:25.] They are distinct from one another in their relations of origin: "It is the Father who generates, the Son who is begotten, and the Holy Spirit who proceeds." [Lateran Council IV (1215): DS 804.] The divine Unity is Triune. [468, 689]
255 The divine persons are relative to one another. Because it does not divide the divine unity, the real distinction of the persons from one another resides solely in the relationships which relate them to one another: "In the relational names of the persons the Father is related to the Son, the Son to the Father, and the Holy Spirit to both. While they are called three persons in view of their relations, we believe in one nature or substance." [Council of Toledo XI (675): DS 528.] Indeed "everything (in them) is one where there is no opposition of relationship." [Council of Florence (1442): DS 1330.] "Because of that unity the Father is wholly in the Son and wholly in the Holy Spirit; the Son is wholly in the Father and wholly in the Holy Spirit; the Holy Spirit is wholly in the Father and wholly in the Son." [Council of Florence (1442): DS 1331.] 
256 St. Gregory of Nazianzus, also called "the Theologian", entrusts this summary of Trinitarian faith to the catechumens of Constantinople: [236, 684, 84]
Above all guard for me this great deposit of faith for which I live and fight, which I want to take with me as a companion, and which makes me bear all evils and despise all pleasures: I mean the profession of faith in the Father and the Son and the Holy Spirit. I entrust it to you today. By it I am soon going to plunge you into water and raise you up from it. I give it to you as the companion and patron of your whole life. I give you but one divinity and power, existing one in three, and containing the three in a distinct way. Divinity without disparity of substance or nature, without superior degree that raises up or inferior degree that casts down... the infinite co-naturality of three infinites. Each person considered in himself is entirely God... the three considered together... I have not even begun to think of unity when the Trinity bathes me in its splendour. I have not even begun to think of the Trinity when unity grasps me.. [St. Gregory of Nazianzus, Oratio 40, 41: PG 36,417.]
IV. THE DIVINE WORKS AND THE TRINITARIAN MISSIONS
257 "O blessed light, O Trinity and first Unity!" [LH, Hymn for Evening Prayer.] God is eternal blessedness, undying life, unfading light. God is love: Father, Son and Holy Spirit. God freely wills to communicate the glory of his blessed life. Such is the "plan of his loving kindness", conceived by the Father before the foundation of the world, in his beloved Son: "He destined us in love to be his sons" and "to be conformed to the image of his Son", through "the spirit of sonship". [Eph 1:4-5, 9; Rom 8:15, 29.] This plan is a "grace [which] was given to us in Christ Jesus before the ages began", stemming immediately from Trinitarian love. [2 Tim 1:9-10.] It unfolds in the work of creation, the whole history of salvation after the fall, and the missions of the Son and the Spirit, which are continued in the mission of the Church. [Cf. AG 2-9.] [221, 758, 292, 850]
258 The whole divine economy is the common work of the three divine persons. For as the Trinity has only one and the same natures so too does it have only one and the same operation: "The Father, the Son and the Holy Spirit are not three principles of creation but one principle." [Council of Florence (1442): DS 1331; cf. Council of Constantinople II (553): DS 421.] However, each divine person performs the common work according to his unique personal property. Thus the Church confesses, following the New Testament, "one God and Father from whom all things are, and one Lord Jesus Christ, through whom all things are, and one Holy Spirit in whom all things are". [Council of Constantinople II: DS 421.] It is above all the divine missions of the Son's Incarnation and the gift of the Holy Spirit that show forth the properties of the divine persons. 
259 Being a work at once common and personal, the whole divine economy makes known both what is proper to the divine persons, and their one divine nature. Hence the whole Christian life is a communion with each of the divine persons, without in any way separating them. Everyone who glorifies the Father does so through the Son in the Holy Spirit; everyone who follows Christ does so because the Father draws him and the Spirit moves him. [Cf. Jn 6:44; Rom 8:14.] 
260 The ultimate end of the whole divine economy is the entry of God's creatures into the perfect unity of the Blessed Trinity. [Cf. Jn 17:21-23.] But even now we are called to be a dwelling for the Most Holy Trinity: "If a man loves me", says the Lord, "he will keep my word, and my Father will love him, and we will come to him, and make our home with him": [Jn 14:23.] [1050, 1721, 1997]
O my God, Trinity whom I adore, help me forget myself entirely so to establish myself in you, unmovable and peaceful as if my soul were already in eternity. May nothing be able to trouble my peace or make me leave you, O my unchanging God, but may each minute bring me more deeply into your mystery! Grant my soul peace. Make it your heaven, your beloved dwelling and the place of your rest. May I never abandon you there, but may I be there, whole and entire, completely vigilant in my faith, entirely adoring, and wholly given over to your creative action. [Prayer of Blessed Elizabeth of the Trinity.] 
261 The mystery of the Most Holy Trinity is the central mystery of the Christian faith and of Christian life. God alone can make it known to us by revealing himself as Father, Son and Holy Spirit.
262 The Incarnation of God's Son reveals that God is the eternal Father and that the Son is consubstantial with the Father, which means that, in the Father and with the Father the Son is one and the same God.
263 The mission of the Holy Spirit, sent by the Father in the name of the Son (Jn 14:26) and by the Son "from the Father" (Jn 15:26), reveals that, with them, the Spirit is one and the same God. "With the Father and the Son he is worshipped and glorified" (Nicene Creed).
264 "The Holy Spirit proceeds from the Father as the first principle and, by the eternal gift of this to the Son, from the communion of both the Father and the Son" (St. Augustine, De Trin. 15, 26, 47: PL 42, 1095).
265 By the grace of Baptism "in the name of the Father and of the Son and of the Holy Spirit", we are called to share in the life of the Blessed Trinity, here on earth in the obscurity of faith, and after death in eternal light (cf. Paul VI, CPG 9).
266 "Now this is the Catholic faith: We worship one God in the Trinity and the Trinity in unity, without either confusing the persons or dividing the substance; for the person of the Father is one, the Son's is another, the Holy Spirit's another; but the Godhead of the Father, Son and Holy Spirit is one, their glory equal, their majesty coeternal" (Athanasian Creed: DS 75; ND 16).
267 Inseparable in what they are, the divine persons are also inseparable in what they do. But within the single divine operation each shows forth what is proper to him in the Trinity, especially in the divine missions of the Son's Incarnation and the gift of the Holy Spirit.
Paragraph 3. The Almighty
268 Of all the divine attributes, only God's omnipotence is named in the Creed: to confess this power has great bearing on our lives. We believe that his might is universal, for God who created everything also rules everything and can do everything. God's power is loving, for he is our Father, and mysterious, for only faith can discern it when it "is made perfect in weakness". [Cf. Gen 1:1; Jn 1:3; Mt 6:9; 2 Cor 12:9; cf. 1 Cor 1:18.] 
"He does whatever he pleases" [Ps 115:3.]
269 The Holy Scriptures repeatedly confess the universal power of God. He is called the "Mighty One of Jacob", the "LORD of hosts", the "strong and mighty" one. If God is almighty "in heaven and on earth", it is because he made them. [Gen 49:24; Is 1:24 etc.; Pss 24:8-10; 135 6.] Nothing is impossible with God, who disposes his works according to his will. [Cf. Jer 27:5; 32:17; Lk 1:37.] He is the Lord of the universe, whose order he established and which remains wholly subject to him and at his disposal. He is master of history, governing hearts and events in keeping with his will: "It is always in your power to show great strength, and who can withstand the strength of your arm? [Wis 11:21; cf. Esth 4:17b; Prov 21:1; Tob 13:2.] 
"You are merciful to all, for you can do all thing" [Wis 11:23.]
270 God is the Father Almighty, whose fatherhood and power shed light on one another: God reveals his fatherly omnipotence by the way he takes care of our needs; by the filial adoption that he gives us ("I will be a father to you, and you shall be my sons and daughters, says the Lord Almighty"): [2 Cor 6:18; cf. Mt 6:32.] finally by his infinite mercy, for he displays his power at its height by freely forgiving sins. [2777, 1441]
271 God's almighty power is in no way arbitrary: "In God, power, essence, will, intellect, wisdom, and justice are all identical. Nothing therefore can be in God's power which could not be in his just will or his wise intellect." [St. Thomas Aquinas, STh I, 25, 5, ad I.]
The mystery of God's apparent powerlessness
272 Faith in God the Father Almighty can be put to the test by the experience of evil and suffering. God can sometimes seem to be absent and incapable of stopping evil. But in the most mysterious way God the Father has revealed his almighty power in the voluntary humiliation and Resurrection of his Son, by which he conquered evil. Christ crucified is thus "the power of God and the wisdom of God. For the foolishness of God is wiser than men, and the weakness of God is stronger than men." [1 Cor 1:24-25.] It is in Christ's Resurrection and exaltation that the Father has shown forth "the immeasurable greatness of his power in us who believe". [Eph 1:19-22.] [309, 412, 609, 648]
273 Only faith can embrace the mysterious ways of God's almighty power. This faith glories in its weaknesses in order to draw to itself Christ's power. [Cf. 2 Cor 12:9; Phil 4:13.] The Virgin Mary is the supreme model of this faith, for she believed that "nothing will be impossible with God", and was able to magnify the Lord: "For he who is mighty has done great things for me, and holy is his name." [Lk 1:37, 49.] 
274 "Nothing is more apt to confirm our faith and hope than holding it fixed in our minds that nothing is impossible with God. Once our reason has grasped the idea of God's almighty power, it will easily and without any hesitation admit everything that [the Creed] will afterwards propose for us to believe - even if they be great and marvellous things, far above the ordinary laws of nature." [Roman Catechism I, 2, 13] [1814, 1817]
275 With Job, the just man, we confess: "I know that you can do all things, and that no purpose of yours can be thwarted" (Job 42:2).
276 Faithful to the witness of Scripture, the Church often addresses her prayer to the "almighty and eternal God" ("omnipotens sempiterne Deus..."), believing firmly that "nothing will be impossible with God" (Gen 18:14; Lk 1:37; Mt 19:26).
277 God shows forth his almighty power by converting us from our sins and restoring us to his friendship by grace. "God, you show your almighty power above all in your mercy and forgiveness..." (Roman Missal, 26th Sunday, Opening Prayer).
278 If we do not believe that God's love is almighty, how can we believe that the Father could create us, the Son redeem us and the Holy Spirit sanctify us?