Mark 1:4

And in fulfillment of this, John the Baptizer appeared in the Wilderness, proclaiming a baptism upon repentance, for the forgiveness of sins.

Luke 1:77

To give his people the knowledge of salvation In the forgiveness of their sins,

Matthew 3:1-2

About that time John the Baptist first appeared, proclaiming in the Wilderness of Judea:

Matthew 3:6

And were baptized by him in the river Jordan, confessing their sins.

Matthew 3:11

I, indeed, baptize you with water to teach repentance; but He who is Coming after me is more powerful than I, and I am not fit even to carry his sandals. He will baptize you with the Holy Spirit and with fire.

Luke 3:2-3

And when Annas and Caiaphas were High Priests, a Command from God came to John, the son of Zechariah, while he was in the wilderness.

John 3:23

John, also, was baptizing at Aenon near Salim, because there were many streams there; and people were constantly coming and being baptized.

Acts 10:37

You yourselves know the story which spread through all Judea, how, beginning form Galilee, after the baptism which John proclaimed--

Acts 13:24-25

John having first proclaimed, before the appearance of Jesus, a baptism upon repentance for all the people of Israel.

Acts 19:3-4

"What then was your baptism?" Paul asked.

Acts 22:16

And now why wait any longer: Be baptized at once, wash away your sins, and invoke 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
About that time John the Baptist first appeared, proclaiming in the Wilderness of Judea:
Luke 3:2
And when Annas and Caiaphas were High Priests, a Command from God came to John, the son of Zechariah, while he was in the wilderness.
John 3:23
John, also, was baptizing at Aenon near Salim, because there were many streams there; and people were constantly coming and being baptized.
Acts 10:37
You yourselves know the story which spread through all Judea, how, beginning form Galilee, after the baptism which John proclaimed--
Acts 13:24
John having first proclaimed, before the appearance of Jesus, a baptism upon repentance for all the people of Israel.
Acts 19:3
"What then was your baptism?" Paul asked.

Remission

Acts 22:16
And now why wait any longer: Be baptized at once, wash away your sins, and invoke his Name.