John 1:8

He was not the light, but came that he might bear witness of the light.

John 1:20

And he confessed, and denied not; and he confessed, I am not the Christ.

John 3:28

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

Acts 19:4

And Paul said, John baptized with the baptism of repentance, saying unto the people that they should believe on him that should come 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 confessed, and denied not; and he confessed, I am not the Christ.
John 3:28
Ye yourselves bear me witness, that I said, I am not the Christ, but, that I am sent before him.
Acts 19:4
And Paul said, John baptized with the baptism of repentance, saying unto the people that they should believe on him that should come 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
when John had first preached before his coming the baptism of repentance to all the people of Israel.

American Standard Version Public Domain