Note 3 at Mt 17:12: Jesus clearly indicated John the Baptist as being the one who fulfilled the last prophecy of the Old Testament: the coming of Elijah the prophet before the great and dreadful day of the Lord (Mal 4:5-6). This was the second time that Jesus had said that John the Baptist was the fulfillment of Malachi's prophecy (Mt 11:14), yet it wasn't until this explanation that the disciples understood what He said (Mt 17:13). The angel Gabriel also quoted from this prophecy and applied it to John the Baptist when announcing his birth to Zacharias (Lu 1:17).

Some people believe that John came only in the spirit and power of Elijah (Lu 1:17). They believe there is yet to be a real appearance of Elijah before the second advent of Jesus and that he is one of the two witnesses spoken of in Re 11:3-12. It is certain that John the Baptist was not a reincarnation of Elijah, as some have tried to say, since Elijah never died but was taken into heaven (2Ki 2:11). The Bible does not teach reincarnation. John simply had the same anointing and power upon him that was upon Elijah.