The Trinity

The Trinity is the central mystery of the Christian faith: there is one God in three Persons, the Father, the Son and the Holy Spirit. The three are one and the same God, equal and eternal, sharing one divine life. This mystery surpasses the powers of reason; it is known because God revealed it. Scripture names the three together in one blessing: “The grace of our Lord Jesus Christ and the charity of God and the communication of the Holy Ghost be with you all. Amen.” 2 Corinthians 13:13

One God

There is only one God, one divine nature, what God is. The faith received from Israel holds this unity as the first of all, and confesses it as the foundation of all the rest: “Hear, O Israel, the Lord our God is one Lord.” Deuteronomy 6:4

The Father, the Son and the Holy Spirit are the one God. Each is wholly God, possessing the same and only divine nature, without dividing it or multiplying it.

Three Persons

In this one God, there are three Persons, that is, three distinct “someones”, each of whom is fully God. To speak this mystery without betraying it, the Church forged a precise vocabulary: what God is, the one divine nature, the Greeks named ousia (οὐσία), which Latin renders as substantia; what each of the three is, a distinct subject that subsists, they named hypostasis (ὑπόστασις), which Latin renders as persona, Person. The faith thus confesses one substance in three Persons, a language settled in the fourth century by the Cappadocian Fathers, Saint Basil of Caesarea, Saint Gregory of Nazianzus and Saint Gregory of Nyssa, so that the Persons are never confounded nor the substance divided. The Father is the source without origin; the Son is begotten of him from all eternity; the Spirit proceeds from the Father and the Son. The three Persons are equal in dignity and coeternal. “I and the Father are one.” John 10:30

Knowing and loving in God

Saint Augustine showed where to look for a reflection of this mystery: in the human soul, which bears its image. Our spirit acts by two powers: the intellect, which knows, and the will, which loves. It is by them that man is said to be made in the image of God: he bears within him the power to know and to love, as God knows and loves. “Let us make man to our image and likeness.” Genesis 1:26

This likeness, however, has its measure, for God is infinitely simple. In us, the intellect and the will are two distinct powers of the soul, and their acts, the idea the intellect conceives and the love the will bears, are but passing states that cross us without being ourselves. In God, his act of knowing and his act of loving are his very essence, the one and the same God.

In him, these two acts bear an eternal fruit. Knowing himself perfectly, the Father expresses all that he is in his living Word. “In the beginning was the Word, and the Word was with God, and the Word was God.” John 1:1 This Word receives the whole divine essence and subsists as a Person, the Son. Likewise, the love with which the Father and the Son love each other receives the whole essence and subsists as a Person, the Spirit. The Son is thus begotten by way of knowledge, and the Spirit proceeds by way of love.

Distinct by their relations

The three Persons are distinguished by their relations of origin, and by these alone. The Father begets, the Son is begotten, the Spirit proceeds: this is all that distinguishes them, and it suffices to make them truly distinct, while remaining the one God. All that they are, they are together, except for what the relation distinguishes. Distinct, the three Persons are nevertheless never separated: each dwells wholly in the other two, without mingling or being confounded, what the Greeks named perichoresis and the Latins circumincession, the mutual indwelling of the Persons. Christ says it of himself and the Father. “Believe me: I am in the Father, and the Father is in me.” John 14:11 The Spirit proceeds from the Father and is sent by the Son: “when the Paraclete cometh, whom I will send you from the Father, the Spirit of truth, who proceedeth from the Father.” John 15:26 This Spirit is also the Spirit of the Son, who gives him as his own: “God has sent into our hearts the Spirit of his Son.” Galatians 4:6 The Son has part in this origin, for he receives from the Father all that the Father has, even to making the Spirit proceed with him: “All things whatsoever the Father hath are mine. Therefore I said that he shall receive of me.” John 16:14-15 The Spirit therefore proceeds from the Father and the Son as from one principle, the Father remaining the source without origin, who grants the Son to make him proceed with him. This is why the Church confesses that the Spirit proceeds from the Father and the Son.

Revealed by Christ

Christ revealed this mystery hidden in God. We do not know it by scrutinising from without the eternal life of God, but by watching how he acts to save us: the Father sends the Son into the flesh, the Father and the Son send the Spirit into hearts. These sendings are called the divine missions, and each prolongs in time an eternal origin, the Son sent because he is begotten, the Spirit given because he proceeds; thus the Trinity as it gives itself in the history of salvation makes known the Trinity as it is in itself. “But when the fulness of the time was come, God sent his Son, made of a woman.” Galatians 4:4 In coming among men, the Son made the Father known and promised the Spirit. At the moment of his baptism in the Jordan, the three are manifested together: the Son in the water, the Spirit as a dove, the Father by his voice: “He saw the Spirit of God descending like a dove and coming upon him, and a voice from heaven said: This is my beloved Son.” Matthew 3:16-17 At the moment of leaving his own, Christ entrusted the whole mystery to the command to baptise: “Going therefore, teach ye all nations: baptizing them in the name of the Father and of the Son and of the Holy Ghost.” Matthew 28:19 One name, and three who bear it: the unity of nature and the trinity of Persons are held in this formula, which the Church pronounces over every baptised person.

The Father

First Person, the Father is the origin without origin, from whom the Son and the Spirit come. Creation is the work of the three Persons together, for all that God accomplishes outside himself, he accomplishes as one God, by one undivided action; and so the Creed refers creation to the Father, redemption to the Son, sanctification to the Spirit, not that they share out the task, but because to each Person is ascribed the common work that best answers to what distinguishes each, which is called an appropriation. Creation is thus attributed first to the Father because he is the source without origin. The one God calls the world into being by his word alone and holds it in life at every moment, down to the smallest detail. “In the beginning God created heaven, and earth.” Genesis 1:1

If God is called Father, it is first because he eternally begets his Son: fatherhood is in him before it is in any creature, and all human fatherhood descends from it as a reflection. “I bow my knees to the Father of our Lord Jesus Christ, Of whom all paternity in heaven and earth is named.” Ephesians 3:14-15

The Father is Father of the only Son from all eternity, and he becomes the Father of men by adopting them. Through the grace of baptism, the Spirit of the Son is given to the believer, who then addresses God as his Father. “you have received the spirit of adoption of sons, whereby we cry: Abba (Father).” Romans 8:15

The Son

Second Person, the Son is the Word of God, begotten of the Father from all eternity, of the same nature as he: God born of God. Against Arius, a priest of Alexandria who held the Son to be the highest of creatures drawn from nothing, the Council of Nicaea, in 325, confessed that the Son is consubstantial with the Father, in Greek homoousios (ὁμοούσιος), of one and the same divine substance: not created, but begotten, true God born of true God. The perfect image of the Father, he is the one in whom the Father knows and gives himself fully. “Who being the brightness of his glory and the figure of his substance.” Hebrews 1:3

The prologue of the Gospel of John was written in Greek, and the word it uses is Logos (λόγος), which says at once speech and reason: the word one utters, and the intelligence and order expressed in it. To name the Son “Logos” is to confess him at once the Word that the Father utters and the Wisdom by which he thinks and orders the world. Greek thought already called “logos” the reason that runs through the universe; John takes up this word and reveals that this Logos is a Person, God himself. Translated into Latin, “Logos” became “Verbum”, from which comes the English “Word”.

The Father creates all things through the Son, his Word: God says, and it is; this creative word is the Word himself, by whom the Father calls all things into being and holds them in existence. “All things were made by him: and without him was made nothing that was made.” John 1:3

To save men, the Son took our human nature: conceived by the Holy Spirit and born of the Virgin Mary, he became true man without ceasing to be true God, uniting in his Person the two natures, divine and human, out of love and for our salvation. “And the Word was made flesh and dwelt among us, and we saw his glory.” John 1:14

The Holy Spirit

Third Person, the Holy Spirit proceeds from the Father and the Son by way of love: he is the Love with which they love each other and the Gift in which they give themselves wholly, the Lord acting in the heart of men. “Now the Lord is a Spirit. And where the Spirit of the Lord is, there is liberty.” 2 Corinthians 3:17

The Spirit escapes the gaze, and Scripture makes him known through images. The word that names him, ruah (רוּחַ) in Hebrew, pneuma (πνεῦμα) in Greek, means at once breath, wind and spirit. The wind is his most telling image: “The Spirit breatheth where he will and thou hearest his voice: but thou knowest not whence he cometh and whither he goeth. So is every one that is born of the Spirit.” John 3:8 The dove, descending upon Christ at his baptism in the Jordan, marks him out as the Messiah, the one on whom the Spirit rests. Already, after the flood, a dove had returned to Noah, a sign that the judgment was past and the earth restored to life: “she came to him in the evening carrying a bough of an olive tree, with green leaves, in her mouth. Noe therefore understood that the waters were ceased upon the earth.” Genesis 8:11 The same sign, on the Jordan, announces the peace of the new creation.

Fire speaks of the transforming power of the Spirit: it purifies, as the flame refines metal, and enkindles the heart with the charity of God; on the morning of Pentecost, it rested on the disciples in tongues of flame. John the Baptist had foretold it: “he shall baptize you in the Holy Ghost and fire.” Matthew 3:11 The anointing shows him consecrating and strengthening the one he seizes: oil penetrates what it touches and steeps into it deeply, and so the Spirit pervades the whole soul. He is the very anointing from which Christ takes his name, the Greek word rendered “Anointed”, Christos (χριστός): “God anointed Jesus of Nazareth with the Holy Spirit and with power.” Acts 10:38 The Christian receives this seal at baptism and confirmation.

He is the Lord who gives life: present from the origin over creation, he bears in man the new life of God, and he made the prophets speak and inspired the Scriptures. At the Council of Constantinople, in 381, gathered against those who lowered the Spirit to the rank of a creature, the Church confessed that he is the Lord who gives life, who proceeds from the Father, and who with the Father and the Son receives one same adoration and one same glory: his divinity is entire, equal to that of the Father and the Son. Before his Passion, Christ promised him under the name of Paraclete, the Greek word paraklētos (παράκλητος) meaning the one called alongside to defend and console; on the day of Pentecost, he descends upon the disciples and brings the Church to birth. “They were all filled with the Holy Spirit.” Acts 2:4 Since then, he abides in the Church and leads her into all truth.

The Holy Spirit dwells in the soul of the baptised by sanctifying grace: he pours into it the love of God and sustains prayer. “And hope confoundeth not: because the charity of God is poured forth in our hearts, by the Holy Ghost who is given to us.” Romans 5:5 He fills the believer with his gifts. The prophecy of Isaiah enumerates them: “Upon him will rest the Spirit of the Lord: a spirit of wisdom and understanding, a spirit of counsel and fortitude, a spirit of knowledge and of the fear of the Lord.” Isaiah 11:2 The tradition counts seven, adding piety. Where he reigns, these gifts ripen into fruits, the visible marks of a life he leads. “the fruit of the Spirit is, charity, joy, peace, patience, benignity, goodness, longanimity, Mildness, faith, modesty, continency, chastity.” Galatians 5:22-23

A communion of love

The inner life of God is an exchange of love among the three Persons, given and received without end. This love is what God is: “for God is charity.” 1 John 4:8

Through sanctifying grace, God brings man into this life: the Trinity comes to dwell in the soul of the baptised and associates him to its own communion. The end of man is to share for ever in this love, the very love with which the Father loves the Son: “I have made known thy name to them, and will make it known: that the love wherewith thou hast loved me may be in them, and I in them.” John 17:26