First, the word “for” (eis) can mean either “with a view to” or “because of.” In the latter case, water baptism would be because they had been saved, not in order to be saved.
Second, people are saved by receiving God’s Word, and Peter’s audience “gladly received his word” before they were baptized (Acts 2:41).
Third, verse 44 speaks of “all who believed” as constituting the early church, not all who were baptized.
Fourth, later, those who believed Peter’s message clearly received the Holy Spirit before they were baptized. Peter said, “Can anyone forbid water, that these should not be baptized who have received the Holy Spirit just as we have?” (Acts 10:47).
Fifth, Paul separates baptism from the gospel, saying, “Christ did not send me to baptize, but to preach the gospel” (1 Cor. 1:17a nasb). But it is the gospel that saves us (Rom. 1:16). Therefore, baptism is not part of what saves us.
Sixth, Jesus referred to baptism as a work of righteousness (Matt. 3:15). But the Bible declares clearly it is “not because of righteous things we have done, but because of his mercy. He saved us through the washing of rebirth and renewal by the Holy Spirit” (Titus 3:5 niv).
Seventh, not once in the entire Gospel of John, written explicitly so that people could believe and be saved (John 20:31), is baptism noted as a condition of salvation. Rather this Gospel instructs people to “believe” to be saved (cf. John 3:16, 18, 36).
It seems best to understand Peter’s statement like this: “Repent and be baptized as a result of the forgiveness of sins.” That this view looked backward to their sins being forgiven at the moment when they were saved is made clear by the context and the rest of Scripture. Believing or repenting and being baptized are placed together, since baptism should follow belief. But nowhere does it say, “He who is not baptized will be condemned” (cf. Mark 16:16). Yet Jesus said emphatically that “whoever does not believe stands condemned already” (John 3:18b niv, emphasis added). Scripture does not make baptism a condition of salvation.
Commentary taken from the book titled When Cultists Ask, By Norman Geisler and Ron Rhodes