Mark 9:11
And they asked him, why do the teachers of the law say that Elijah must come first? — the question about Elijah follows naturally from the transfiguration appearance of Elijah: if Elijah appeared at the transfiguration, what is his relationship to the scribal expectation that Elijah comes first (before the Messiah, Malachi 4:5)? The question is a real theological puzzle: has Elijah come? Is the transfiguration appearance the fulfillment? Or is the expectation still outstanding?