Luke 3:3

And he came into all the region round about the Jordan preaching the baptism of repentance unto the remissions of sins,

Luke 1:77

to give knowledge of salvation to His people in remission of their sins,

Matthew 3:5-6

Then Jerusalem and all Judea, and all the region about the Jordan, were coming out to him,

Matthew 3:11

I indeed baptize you with water unto repentance, but there is One coming after me more powerful than I, whose sandals I am not worthy to carry; He will baptize you with the Holy Ghost and fire.

Mark 1:4-5

John the Baptist came preaching in the wilderness the baptism of repentance unto the remission of sins.

John 1:28

These things took place in Bethany beyond the Jordan, where John was baptizing.

John 1:31-33

And I did not know Him, but in order that He may be made manifest to Israel, on this account I came baptizing with water.

John 3:26

And they came to John, and said to him, Rabbi, He who is with thee beyond the Jordan, to whom thou hast borne witness, behold, the same baptizeth, and all are coming to Him.

Acts 13:24

and John having preached the baptism of repentance to all the people of Israel, before the face of his coming.

Acts 19:4

And Paul said, John baptized with the baptism of repentance, saying unto the people, that they should believe on the one coming after him, that is Jesus.

Acts 22:16

And now why tarriest thou? arising, be baptized, and wash away thy sins, calling on His name.

Treasury of Scripture Knowledge

Summary

And he came into all the country about Jordan, preaching the baptism of repentance for the remission of sins;

For

Bible References

The country

Matthew 3:5
Then Jerusalem and all Judea, and all the region about the Jordan, were coming out to him,
Mark 1:4
John the Baptist came preaching in the wilderness the baptism of repentance unto the remission of sins.
John 1:28
These things took place in Bethany beyond the Jordan, where John was baptizing.
John 3:26
And they came to John, and said to him, Rabbi, He who is with thee beyond the Jordan, to whom thou hast borne witness, behold, the same baptizeth, and all are coming to Him.

Preaching

Matthew 3:6
and were being baptized by him in the river Jordan, confessing their sins.
Mark 1:4
John the Baptist came preaching in the wilderness the baptism of repentance unto the remission of sins.
John 1:31
And I did not know Him, but in order that He may be made manifest to Israel, on this account I came baptizing with water.
Acts 13:24
and John having preached the baptism of repentance to all the people of Israel, before the face of his coming.
Acts 19:4
And Paul said, John baptized with the baptism of repentance, saying unto the people, that they should believe on the one coming after him, that is Jesus.
Acts 22:16
And now why tarriest thou? arising, be baptized, and wash away thy sins, calling on His name.

For

Luke 1:77
to give knowledge of salvation to His people in remission of their sins,