John 1:8

He was not the Light; but he came to testify of the Light.

John 1:20

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

John 3:28

You yourselves will testify for me, that I said, I am not the Christ, but that I am sent before him.

Acts 19:4

And Paul said: John immersed with the immersion of repentance, saying to the people, that they must believe on him who should come after him, that is, on the Christ, 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 did not deny; and he confessed: I am not the Christ.
John 3:28
You yourselves will testify for me, that I said, I am not the Christ, but that I am sent before him.
Acts 19:4
And Paul said: John immersed with the immersion of repentance, saying to the people, that they must believe on him who should come after him, that is, on the Christ, Jesus.

General references

Mark 11:30
Was the immersion of John from heaven, or from men? answer me.
Acts 13:24
John having first preached, before his coming, the immersion of repentance to all the people of Israel.