Christians are baptized “in the name”, not names, “of the Father and of the Son and of the Holy Spirit.” The Trinity is the central mystery of Christian faith: God's own inner life, which we could never have guessed, revealed by Jesus.
The Church teaches the Trinity with careful words:
- There is one God: one divine nature, or substance.
- There are three Persons: the Father, the Son and the Holy Spirit, each fully God.
- The Persons are really distinct from one another by their relations: the Father begets, the Son is begotten, and the Holy Spirit proceeds from the Father and the Son.
The Trinity is not three gods, nor one God wearing three masks. Comparisons can help, but every one of them falls short. Saint Patrick's shamrock, three leaves on one stem, shows oneness and threeness. Water as ice, liquid and steam is misleading, because God is not one Person changing forms. The mystery is greater than any picture.
Saint John wrote that “God is love.” Love needs a lover, a beloved and the love between them. From all eternity the Father loves the Son, the Son loves the Father, and the Holy Spirit is their love. God was never lonely: God is a communion of love.
The whole Trinity acts in everything God does, but we link each Person especially with certain works: creation with the Father, redemption with the Son and making us holy with the Holy Spirit. Through Baptism, the Trinity comes to dwell in us: we become sons and daughters of the Father, brothers and sisters of the Son, and temples of the Holy Spirit.
Because we are made in the image of a God who is communion, we are made for relationships: family, friendship and the Church. We are most ourselves when we give ourselves in love. Every Sign of the Cross is a small creed and a reminder of whose we are.