Did Matthew Copy Luke or Luke Matthew?

In this thread, which is supposed to be on the lost writings of early Christianity that I would most like to have discovered, I can’t seem to get away from Q, Several readers have asked a pointed question about Q. If you recall, Q is the hypothetical document that contained principally sayings of Jesus, that was evidently used by Matthew and Luke (but not by Mark) in constructing their Gospels. The logic is that if Matthew and Luke both used Mark (which the vast majority of scholars agree abo...