John 1:6-8

There was a man sent from God, whose name was John. He came as a witness, to bear witness about the light, that all might believe through him. He was not the light, but came to bear witness about the light.

John 1:6-8

Jesus is the light that shines in the darkness.  After much about him and how he was in the beginning and all things were made through him, we now switch to talking about John the baptist.  Now, it doesn't say "John the Baptist", but it only says "John".  However, we know that this is John the Baptist because it talks about the person sent from God to witness about Jesus.  This is John the Baptist.  He is the one who meant to prepare the way.

In any case, we read here that he was sent from God and came as a witness.  What does he witness?  He came to bear witness about the light.  For what purpose?  The purpose is so that all might believe through him.  So, that they might believe in Jesus through what John says.

Just to make it clear, it is mentioned again that "He was not the light".  Don't be confused because John the Baptist is not the Word, not the Light, not the one they are expecting.  He is only one who comes to bear witness about the light.  He prepares the way for Jesus.