John 1:8

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

Cross References (ranked by relevance)

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

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

Then said Paul, John verily baptized with the baptism of repentance, saying unto the people, that they should believe on him which should come after him, that is, on Christ Jesus.