John 13:19
John 13:1919I am telling you now before it happens, so that when it comes to pass, you will believe that I am He.
Read as a simple messianic identification — "you may believe that I am he," meaning the Christ. The same Greek phrase ego eimi appears in the blind man's "I am he" at , and the Watchtower uses that parallel to argue that ego eimi carries no divine weight here.
The Old Testament background is — Jehovah saying "that you may know and believe me and understand that I am he" (ani hu in Hebrew, ego eimi in the Septuagint). Jesus in echoes the same structure word-for-word: predictive announcement, purpose clause, unpredicated ego eimi. He is putting himself in the place Isaiah 43 reserves for Jehovah. Pair with (Jesus makes belief in his identity a salvation issue), (Abraham), and (the soldiers fall back when Jesus says ego eimi). The "blind man at " parallel collapses on context: the blind man uses ego eimi as ordinary self-identification ("that's me"); Jesus uses it absolutely, in echo of Isaiah 43, as the condition of forgiveness for sins.