When John began preaching repentance, many were probably not sure exactly why. There were many messianic and apocalyptic expectations among the Jewish people of this time, and seeing a striking figure like John would raise the question, “Is he the one we expect? On what authority does he act?”
“Who are you?” the priests and Levites ask. John immediately says that he is not the Christ, i.e., the Messiah. He has not come to redeem or deliver the people, but to prepare them for the One Who will: Jesus. This provokes the next question.
“What then? Are you Elijah?” Certain interpretations of Malachi 4:5 and Sirach 48:1-10 led to the popular belief that Elijah would literally return to anoint the Messiah. John denies that he is Elijah literally returned, in spite of the probable resemblance, based on an extended stay in the desert, his clothing, and his zeal. John is the son of Zechariah and Elizabeth (Lk. 1:57-63) and not Elijah actually returning from the sky in a fiery chariot (cf. 2 Kings 2:11).
When Jesus calls John “Elijah,” He means that John fulfills the words of Malachi and Sirach. John is a “new” Elijah, proclaiming with fiery zeal the advent of Christ and the need for repentance. John emulates Elijah in spirit and as prophet (Lk. 1:17), but he is not the historical figure of 2 Kings.
“Are you the prophet?” Based on Deuteronomy 11:15, many expected the Messiah to be a “new Moses” who would teach the law of God to His people. John, although he is truly a prophet in the spirit of Elijah, rightly denies that he is the new Moses. The prophet is actually Jesus, whom Moses and others foretold. Jesus perfectly fulfills the Mosaic role, preaching the law of charity (e.g., Matthew 5-7, 22:37-40) and redeeming the world through His own life-giving act of charity (cf. Jn. 15:13; Is. 53).
Church Fathers, like Pope St. Gregory the Great, have always held up John as an example of great humility and truth. Although he was the prophet of the Messiah’s advent, he did not make arrogant claims about his unquestionably important role; rather, he simply called himself “the voice crying out in the wilderness,” the herald of deliverance from captivity (cf. Is. 40:3). Such a voice is heard, but gives way or bows to the event greater than the voice. Deliverance is greater than the message that deliverance is coming, so St. John the Baptist humbly states, “He [Jesus] must increase, but I must decrease” (Jn. 3:27-30).
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