Mark 1:4

John was there baptizing in the wilderness, proclaiming a baptism of repentance for the forgiveness of sins.

Luke 1:77

to give knowledge of salvation to his people by the forgiveness of their sins,

Matthew 3:1-2

Now in those days John the Baptist came preaching in the Judean wilderness

Matthew 3:6

and they were being baptized by him in the Jordan River [as they] confessed their sins.

Matthew 3:11

I baptize you with water for repentance, but the one who comes after me is more powerful than I [am], whose sandals I am not worthy to carry. He will baptize you with the Holy Spirit and fire.

Luke 3:2-3

in the time of the high priest Annas and Caiaphas, the word of God came to John the son of Zechariah in the wilderness.

John 3:23

Now John was also baptizing at Aenon near Salim, because water was plentiful there, and they were coming and were being baptized.

Acts 10:37

you know the thing that happened throughout all Judea, beginning from Galilee, after the baptism that John proclaimed:

Acts 13:24-25

Before {his coming} John had publicly proclaimed a baptism of repentance to all the people of Israel.

Acts 19:3-4

And he said, "Into what then were you baptized?" And they said, "Into the baptism of John."

Acts 22:16

And now why are you delaying? Get up, be baptized, and wash away your sins, calling on his name!'

Treasury of Scripture Knowledge

Summary

John did baptize in the wilderness, and preach the baptism of repentance for the remission of sins.

Remission

Bible References

Did

Matthew 3:1
Now in those days John the Baptist came preaching in the Judean wilderness
Luke 3:2
in the time of the high priest Annas and Caiaphas, the word of God came to John the son of Zechariah in the wilderness.
John 3:23
Now John was also baptizing at Aenon near Salim, because water was plentiful there, and they were coming and were being baptized.
Acts 10:37
you know the thing that happened throughout all Judea, beginning from Galilee, after the baptism that John proclaimed:
Acts 13:24
Before {his coming} John had publicly proclaimed a baptism of repentance to all the people of Israel.
Acts 19:3
And he said, "Into what then were you baptized?" And they said, "Into the baptism of John."

Remission

Acts 22:16
And now why are you delaying? Get up, be baptized, and wash away your sins, calling on his name!'