John 1:31

And I did not know him, but in order that he could be revealed to Israel, because of this I came baptizing with water."

Luke 1:17

And he will go on before him in the spirit and power of Elijah, to turn the hearts of the fathers to the children, and the disobedient to the wisdom of the righteous, to prepare for the Lord a people made ready."

Isaiah 40:3-5

A voice [is] calling in the wilderness, "Clear the way of Yahweh! Make a highway smooth in the desert for our God!

Malachi 3:1

"Look! I [am] going to send my messenger, and he will prepare [the] way {before me}. And the Lord whom you [are] seeking will come suddenly to his temple, and the messenger of the covenant, [in] whom you [are] taking pleasure--look!--[he is] about to come," says Yahweh of hosts.

Malachi 4:2-5

But for you who revere my name, the sun of righteousness will rise, with healing in its wings, and you will go out and leap like {fattened calves}.

Matthew 3:6

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

Mark 1:3-5

the voice of one shouting in the wilderness, 'Prepare the way of the Lord, make straight his paths!'"

Luke 1:76-80

And so you, child, will be called the prophet of the Most High, for you will go on before the Lord to prepare his ways,

Luke 2:39-42

And when they had completed everything according to the law of the Lord, they returned to Galilee, to their own town of Nazareth.

Luke 3:3-4

And he went into all the surrounding region of the Jordan, preaching a baptism of repentance for the forgiveness of sins,

John 1:7

This one came for a witness, in order that he could testify about the light, so that all would believe through him.

John 1:33

And I did not know him, but the one who sent me to baptize with water, that one said to me, '[The one] upon whom you see the Spirit descending and remaining upon him--this one is the one who baptizes with the Holy Spirit.'

Acts 19:4

And Paul said, "John baptized [with] a baptism of repentance, telling the people that they should believe in the one who was to come after him--that is, in Jesus."

Treasury of Scripture Knowledge

Summary

And I knew him not: but that he should be made manifest to Israel, therefore am I come baptizing with water.

Bible References

I knew

John 1:33
And I did not know him, but the one who sent me to baptize with water, that one said to me, '[The one] upon whom you see the Spirit descending and remaining upon him--this one is the one who baptizes with the Holy Spirit.'
Luke 1:80
And the child kept growing and becoming strong in spirit, and was in the wilderness until the day of his public appearance to Israel.
Luke 2:39
And when they had completed everything according to the law of the Lord, they returned to Galilee, to their own town of Nazareth.

But

John 1:7
This one came for a witness, in order that he could testify about the light, so that all would believe through him.
Isaiah 40:3
A voice [is] calling in the wilderness, "Clear the way of Yahweh! Make a highway smooth in the desert for our God!
Malachi 3:1
"Look! I [am] going to send my messenger, and he will prepare [the] way {before me}. And the Lord whom you [are] seeking will come suddenly to his temple, and the messenger of the covenant, [in] whom you [are] taking pleasure--look!--[he is] about to come," says Yahweh of hosts.
Malachi 4:2
But for you who revere my name, the sun of righteousness will rise, with healing in its wings, and you will go out and leap like {fattened calves}.
Luke 1:17
And he will go on before him in the spirit and power of Elijah, to turn the hearts of the fathers to the children, and the disobedient to the wisdom of the righteous, to prepare for the Lord a people made ready."

Therefore

Matthew 3:6
and they were being baptized by him in the Jordan River [as they] confessed their sins.
Mark 1:3
the voice of one shouting in the wilderness, 'Prepare the way of the Lord, make straight his paths!'"
Luke 3:3
And he went into all the surrounding region of the Jordan, preaching a baptism of repentance for the forgiveness of sins,
Acts 19:4
And Paul said, "John baptized [with] a baptism of repentance, telling the people that they should believe in the one who was to come after him--that is, in Jesus."