John 1:31

And I knew Him not; but, that He might be manifested to Israel, for this cause I came immersing in water."

Luke 1:17

And he will go before Him in the spirit and power of Elijah, to turn the hearts of the fathers to their children, and the disobedient to walk in the wisdom of the righteous, to make ready for the Lord a people prepared.

Matthew 3:6

and they were being immersed by him in the river Jordan, confessing their sins.

Mark 1:3-5

the voice of one crying in the wilderness, 'Prepare ye the way of the Lord, make His paths straight.'"

Luke 1:76-80

"And you also, child, shall be called 'Prophet of the Most High;' for you shall go before the face of the Lord, to prepare His ways;

Luke 3:3-4

and he came into all the region of the Jordan, preaching the immersion of repentance unto remission of sins;

John 1:7

The same came for a testimony, that he might testify concerning the Light, that all might believe through him.

John 1:33

And I knew Him not; but He who sent me to immerse in water, He said to me, 'Upon Whomsoever you shall see the Spirit descending and abiding on Him, the Same is He Who immerseth in the Holy Spirit.'

Acts 19:4

And Paul said, "John immersed with an immersion of repentance, saying to the people that they should believe on Him coming after him; that is, on 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 knew Him not; but He who sent me to immerse in water, He said to me, 'Upon Whomsoever you shall see the Spirit descending and abiding on Him, the Same is He Who immerseth in the Holy Spirit.'
Luke 1:80
And the child was growing, and becoming strong in spirit, and was in the deserts till the day of his manifestation to Israel.

But

John 1:7
The same came for a testimony, that he might testify concerning the Light, that all might believe through him.
Luke 1:17
And he will go before Him in the spirit and power of Elijah, to turn the hearts of the fathers to their children, and the disobedient to walk in the wisdom of the righteous, to make ready for the Lord a people prepared.

Therefore

Matthew 3:6
and they were being immersed by him in the river Jordan, confessing their sins.
Mark 1:3
the voice of one crying in the wilderness, 'Prepare ye the way of the Lord, make His paths straight.'"
Luke 3:3
and he came into all the region of the Jordan, preaching the immersion of repentance unto remission of sins;
Acts 19:4
And Paul said, "John immersed with an immersion of repentance, saying to the people that they should believe on Him coming after him; that is, on Jesus."