This passage has given rise to the question whether St. Ambrose taught, as some others certainly did (probably on his authority), that baptism in the Name of Christ alone, without mention of the other Persons, is valid. But it is difficult to believe that St. Ambrose meant more than to refer to the passage in the Acts as implying Christian baptism. He says just below that baptism is not complete unless one confess the Father, Son, and Holy Spirit, which would seem to imply the full formula, and he would hardly dissent from St. Basil, who distinctly asserts [De Sp. Sanct. XII.] that baptism without mention of the Three Persons is invalid; and St. Augustine [De Bapt. lib. vi. c. xxv. 47] says that it is more easy to find heretics who reject baptism altogether, than such as omit the right form. Compare also St. Ambrose on St. Luke vi. 67; De Mysteriis, IV. 20; De Sacramentis, II. 5 and 7, especially the latter when he says: In uno nomine…hoc est in nomine Patris et Filii, et Spiritus Sancti.
Editorial footnote · On the Holy Spirit, Chapter III., editorial note cite_note-4 · Original source