How could John the Baptist know all of this about Jesus in the Gospel of John?

[MarcoPG]

A similar question arises with the famous John 3:16. Some editions end the quote before that (therefore making it the evangelist’s narration and therefore “black-letter”), and most others include it in the quote (therefore making the passage Jesus’ words and therefore “red-letter”).

Context would be key, but as mentioned, John’s writing style is such that there are passages where even the context is a little blurred. Eventually, the translators and editors would have to make an educated judgement.

I would say that it wouldn’t shock me to hear this from Jesus Himself, as He knows to be the Son. By the Evanglist it would be normal also, having been instructed by the Son.

If it had been John the Baptist speking, it would have been trickier, since it is not clear that the Baptist new Jesus so well as the Apostle meaning he knew He was the Messiah, but probably did not know He was the eternal Son.