That part of being retrospective is accurate. It wasn't considered dishonest in those days to put later events into the words of speakers before the event. Look at Herodotus. He is writing history, and is the first of the really careful historians. Yet still he has leaders of Athens and Sparta making speeches that accurately "prophesy" exactly how the war goes. Herodotus is using this technique to have the leaders say what they
should have said. Of course, if they had, and been believed, the history would have been different.
And actually, Jesus failed to fulfill the most important prophecy. Nyjbarnes alludes to it, but he forgets that Jesus was specific that the generation in which Jesus' lived would see his return! This caused a lot of problems for the Church then and now. That prophecy is very clear, is by Jesus himself, and it didn't happen.