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, making himself known as he is. Saint Paul names the three together in his blessing: “May the grace of the Lord Jesus Christ, the love of God, and the communion of the Holy Spirit be with you all.” 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, the Lord is one.” 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. The Father is the source without origin. The Son is begotten of the Father from all eternity: he receives the divine life from him as a son receives it from his father, and he is the Word by whom all things were made: “In the beginning was the Word, and the Word was with God, and the Word was God.” John 1:1

The Holy Spirit proceeds from the Father and the Son as the love that unites them. The three Persons are equal in dignity and coeternal. The Son speaks of his unity with the Father: “The Father and I are one.” John 10:30

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 separates 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. Scripture shows the Spirit proceeding from the Father, and sent by the Son: “When the Defender comes, whom I will send to you from the Father, the Spirit of truth who proceeds from the Father.” John 15:26 The Son has part in this origin, for the Spirit receives from him what belongs to the Father: “He will take what is mine; all that the Father has is mine.” John 16:14-15 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. 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

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: “God is love.” 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: “If anyone loves me, he will keep my word, and my Father will love him, and we will come to him and make our home with him.” John 14:23