GOD'S WORD® Translation
John was not the light, but he came to declare the truth about the light.

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

Berean Study Bible
He himself was not the Light, but he came to testify about the Light.

Douay-Rheims Bible
He was not the light, but was to give testimony of the light.

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

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

World English Bible
He was not the light, but was sent that he might testify about the light.

Young's Literal Translation
that one was not the Light, but -- that he might testify about the Light.

John 1:8 Additional Translations ...