This verse teaches that baptism is the point at which a person contacts the blood of Christ and receives forgiveness of sins. In fact, the verse explains that baptism was done in order to obtain that forgiveness. Some, however, have objected to the idea that baptism is necessary for forgiveness and for salvation. The contention is made that the preposition “for” in the phrase “for the remission of sins” means “because of. They assert that the 3,000 people in this passage were baptized because their sins had been forgiven. 

The English word “for” has, as one of its meanings, “because of.” However, the Greek preposition eis that underlies the English word “for” never has a causal function. It always has its primary, basic, accusative thrust: unto, into, to, toward. We must not go to the text, decide what we think it means, and assign a grammatical meaning that coincides with our preconceived understanding. We must begin with the inspired grammar and seek to understand every text in light of the normal, natural, common meaning of the grammatical and lexical construction. The same grammatical construction of Acts 2:38 is found in Matthew 26:28—”into the remission of sins” (eis aphesin hamartion). Jesus’ blood, the blood of the covenant, was undeniably shed for many “in order to acquire remission of sins.” This is the natural and normal meaning of the Greek preposition—toward, in the direction of. Had the Holy Spirit intended to say that baptism is “because of” or “on account of” past forgiveness, He would have used the Greek preposition that conveys that very idea: dia with the accusative. Similarly, in Acts 2:38, if repentance is not “because of” remission of sins, neither is baptism. Peter told his hearers to do both things. 

The act of baptism (connected to the act of repentance) cannot be extricated from the context of remission of sins. In order to receive what these New Testament Christians received (the forgiveness of sins), we must do exactly what they did to receive it (were baptized into Christ for the remission/forgiveness of sins).