John the baptizer appeared in the wilderness, proclaiming a baptism of repentance for the forgiveness of sins. And people from the whole Judean countryside and all the people of Jerusalem were going out to him, and were baptized by him in the river Jordan, confessing their sins. (Mark 1: 4-5)

John did not offer forgiveness. Rather, he offered being prepared for forgiveness through repentence.

The Greek word translated here as repentence is metanoia. This means to change one's mind or purpose. John may have known some Greek, but his worldview was probably rooted in Hebrew. The Hebrew notion of forgiveness - as in shuwb - is to turn back, restore an original purpose, or to refresh.

John perceived that before forgiveness, pardon or release we must prepare. For John we must work with God. In particular, we must not just change our mind or behavior; we must find our original purpose and recommit ourselves to that purpose.