John 1:8

He was not the light, but came to bear witness of the light.

John 1:20

And he declared, and did not deny; and he declared, I am not the Christ.

John 3:28

Ye yourselves bear me witness, that I said, I am not the Christ, but that I was sent before that man.

Acts 19:4

Then said Paul, John indeed baptized with the baptism of repentance, saying to the people, that they should believe on him that was coming after him; that is, on Jesus.

Treasury of Scripture Knowledge

Summary

He was not that Light, but was sent to bear witness of that Light.

General references

Bible References

That light

John 1:20
And he declared, and did not deny; and he declared, I am not the Christ.
John 3:28
Ye yourselves bear me witness, that I said, I am not the Christ, but that I was sent before that man.
Acts 19:4
Then said Paul, John indeed baptized with the baptism of repentance, saying to the people, that they should believe on him that was coming after him; that is, on Jesus.

General references

Mark 11:30
The baptism of John, was it from heaven, or from men? Answer me.
Acts 13:24
before whose coming forward John had first preached a baptism of repentance to all the people of Israel.