Then His disciples asked Him, “Why is it, [since you are obviously the Messiah], that the experts in the Law of Moses say that Elijah must come first?”
And if you are willing to accept [this truth], this person [i.e., John] fulfills [the prophecy of] the coming of Elijah [See Mal. 4:5-6].
Then Elijah, along with Moses, appeared to them and they were talking with Jesus.
So, they kept what He told them to themselves, discussing [only] among themselves what “rising again from the dead” meant.