CLAIM: Jesus said, “If you are willing to accept it, John himself is Elijah who was to come” (Mt. 11:14). John denied that he was Elijah (Jn. 1:21). What does Jesus mean by this? Does he mean that John the Baptist is Elijah?
RESPONSE: The Jews were expecting Elijah to come back before King Messiah shows up. Thus they would’ve been stumbled at Jesus claiming to be the Messiah, when Elijah was no place to be found. And so, Jesus tells them that John the Baptist could play that role, because he’s so similar to Elijah (Lk. 1:17). Of course, since God had foreknowledge of this whole event, he knew that the Jews would reject Jesus, so Elijah didn’t need to come.
The OT predicted that Elijah would return before the end of human history. Malachi predicted that Elijah will appear before “the great and terrible day of the Lord” (Mal. 4:5-6; c.f. 3:1-3). Jesus also said that “Elijah is coming and will restore all things” (Mt. 17:11). Jesus said that John the Baptist was a partial fulfillment of this prophecy, but this was contingent on whether they would receive it (Mt. 11:14). Of course, in his omniscience, God knew that the Jewish people would reject Jesus. Therefore, John the Baptist denied that he was the fulfillment of these passages about Elijah (Jn. 1:21)—even though he did come “in the spirit and power of Elijah” (Lk. 1:17).
God didn’t want this prophecy in Malachi 4:5 to be an unnecessary stumbling block to the Jewish people. So, he sent John the Baptist to play this role. But since God knew they would reject him, he didn’t need to send the real Elijah.