In Acts 2:38, Peter says, “Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Ghost.” When a person is baptised by one holding the priesthood, the following words are used: “Having been commissioned of Jesus Christ, I baptize you in the name of the Father, and of the Son, and of the Holy Ghost.” Why is the baptismal prayer different than what Peter said in Acts?
Peter’s exhortation in the second chapter of Acts that his audience be “baptized” would not have been a new concept to his Jewish audience, who would already have been accustomed to the notion of Jewish ritual baths ormikvot (not to mention the ministry of John the Baptist, who had been executed fewer than five years previously). The thrust of Peter’s sermon is that Israel needs to understand that the great Lawgiver who originated the old Mosaic rituals and traditions–including what we now call baptism–was, in fact, none other than the recently slain Jesus of Nazareth. Peter’s teaching does not prohibit mentions of the Father or the Holy Spirit in the baptismal prayer; it simply reminds us of Jesus’ central role in the baptismal covenant.
It is interesting to note that the precise verbiage of the baptismal prayer seems to have changed somewhat over time. Our modern baptismal prayer comes from Doctrine and Covenants 20:73:
Having been commissioned of Jesus Christ, I baptize you in the name of the Father, and of the Son, and of the Holy Ghost. Amen.
This verbiage is close to, but slightly different from, the form given to the Nephites by the Lord Himself in 3 Nephi 11:25:
Having authority given me of Jesus Christ, I baptize you in the name of the Father, and of the Son, and of the Holy Ghost. Amen.
And in Mosiah 18:13, Alma baptizes Helam using a very different prayer:
Helam, I baptize thee, having authority from the Almighty God, as a testimony that ye have entered into a covenant to serve him until you are dead as to the mortal body; and may the Spirit of the Lord be poured out upon you; and may he grant unto you eternal life, through the redemption of Christ, whom he has prepared from the foundation of the world.
Thus, while it is certainly important that priesthood holders conform to the ritual prayer established by the Church; it would seem that the Lord has authorized the Church to follow relatively minor variations in that prayer over the years. The common factors in all of these variants seem to be the invocation of proper priesthood authority and references to all three members of the Godhead.