CATECHISM OF THE CATHOLIC CHURCH
SECOND EDITION

Paragraphs 230–233

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.
232 Christians are baptized "in the name of the Father and of the Son and of the Holy Spirit" 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."
233 Christians are baptized in the name of the Father and of the Son and of the Holy Spirit: not in their names, for there is only one God, the almighty Father, his only Son and the Holy Spirit: the Most Holy Trinity.