Elijah has already come, and they did not recognize him. In the literature of the end times (also known as the end of the world, the coming of the Messiah, or the second coming of Christ), there is a belief that Elijah, one of the greatest Old Testament prophets, has to come back before the final Parousia occurs. The coming back of Elijah is of great importance because it is his coming that marks the beginning of the end. The coming of Elijah was a much awaited event because it was his responsibility to usher the people into repentance and make them ready for the Messiah (Elijah’s responsibility was to put an end to the Lord’s wrath by turning back the hearts of fathers to their sons, and to re-establish the tribes of Jacob [cf. First Reading]). Jesus’ disciples were definitely aware of this literature concerning the end times. They might also have heard on a couple of occasions Jesus being referred to as the Messiah. If indeed Jesus was the Messiah, why didn’t Elijah appear to usher him? To which Jesus responded, ‘Elijah did indeed come, but you refused to believe him.’
While it is not clear whether Jesus himself subscribed to what the literature of the end times preached, he nonetheless saw in the ministry of John the Baptist the fulfillment of the prophecies of old. He recognized the ministry of John the Baptist as that of preparing the hearts of the people for the reception of the message of the coming of the kingdom. He saw in John’s ministry the foundation of his own ministry. The role of Elijah (John the Baptist) was an important one since the success of the Messiah’s ministry depended on it.