Catechism of the Catholic Church §232 — excerpt
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."
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.
Also cites: St. Caesarius of Arles, Sermo 9, Exp. symb.: CCL 103, 47
