What is the purpose of baptism?
Steve Atkerson states: “John the Baptist explicitly stated the purpose of his baptism when he said, "I baptize you with water for repentance" (Mt 3:11). Did John baptize them so that they could repent or because they already had repented? That is, was John’s baptism a means to repentance or the result of repentance? In both English and Greek, "for" (eis) can refer to either an objective (I left "for" home ) or a cause (I cried "for" joy). In Mt 3:11, "for" denotes a cause; John’s baptism came because they had already repented. It was an outward sign of an inward act. When many of the Pharisees came to be baptized, John condemned them as a "brood of vipers" because they had not yet repented (Mt 3:7-10). Thus, when Luke wrote that John was "preaching a baptism of repentance for the forgiveness of sins" (3:3), he meant that John’s baptism was symbolic of a person’s repentance in order to be forgiven. It was not a "baptism for forgiveness" but rather a baptism that expressed "repentance for forgiveness." Incidentally, "repent" is from metanoia and means "a change of thinking." As such, it is a close parallel to faith; one never occurs without the other. John urged men to change their thinking about sin (Mt 3:6) and to believe in the one coming after him, that is Jesus (Jn 1:6-9; Ac 19:4).”