It's cool that the book of Malachi comes at the end of the English Old Testament in light of the final verses and their fulfillment in the books that immediately follow it. In Malachi 4: 5 – 6 we read,
See, I will send you the prophet Elijah before that great and dreadful day of the LORD comes. 6 He will turn the hearts of the fathers to their children, and the hearts of the children to their fathers; or else I will come and strike the land with a curse.
Jews of that time were expecting a visible and flamboyant return of Elijah, perhaps even in the fiery chariot that he left in.Once announced, the Messiah in power and glory would return to remove the Romans and establish the nation of Israel. The tributes from all the nations would then begin to be brought to Jerusalem (Hag. 2: 7) and everything would be just ducky!
This prophecy must have been an important diagnostic for the religious authorities in identifying the fake messiahs. Anyone announcing that they were the anointed one would have to convince authorities that Elijah had somehow come and anointed them. That would be difficult to fake and that must have been one of the reasons why the authorities had trouble with Jesus.
Justin Martyr was a very prominent second century Christian apologists. He wrote a book titled The Dialogue with Trypho the Jew. This book is a record of a discussion between Justin Martyr and Trypho- a Jewish rabbi. This "dialogue" begins with Justin telling the rabbi that he believes that Jesus was the long awaited Messiah. The following excerpt contains this rabbi's response. It reads:
"When I (Justin) had said this, [the students who were with the rabbi] laughed; but he smiling, says, 'I approve of your other remarks, and admire the eagerness with which you study divine things; but it were better for you abide in the philosophy of Plato… Christ- if he has indeed been born, and exists anywhere… has no power until Elijah comes to anoint him, and make him manifest to all. And you, having accepted a groundless report, invent a Christ for yourselves, and for his sake are inconsiderately perishing."
-Ante Nicene Fathers, Vol. 1, p. 198.
In this one short passage, this rabbi reveals exactly what the Jewish religious leaders and the Jewish people of two thousand years ago were expecting to see before the Messiah appeared. Trypho knew that Jesus could not possibly have been the Messiah because he knew from the unmistakable text of the 'return of Elijah' prophecy that anyone who claimed to be the Christ before Elijah the Prophet had visibly returned from heaven would have to be a false Prophet
John the Baptist was clearly identified by all the gospel writers as filling this role. In Luke the gospel begins with the remarkable circumstances surrounding John's birth and then Luke writes,
And he will go on before the Lord, in the spirit and power of Elijah, to turn the hearts of the fathers to their children and the disobedient to the wisdom of the righteous—to make ready a people prepared for the Lord.
Luke 1: 17
Both Mark and Matthew quote Jesus' response to his disciples about Elijah:
Jesus replied, "To be sure, Elijah comes and will restore all things. But I tell you, Elijah has already come, and they did not recognize him, but have done to him everything they wished. In the same way the Son of Man is going to suffer at their hands." Then the disciples understood that he was talking to them about John the Baptist.
John also describes John the Baptist as “one who was not the light but came to bear witness to the light” (John 1: 6-8). I had not realized until now that John's witness, is a tightly wound component of the full complement of prophetic fulfillment that proved Jesus was who he said he was. Jesus baptism was not just a fulfillment of righteousness (Matt. 3: 13) but was also an anointing for ministry. This is why a significant change in Jesus ministry can be traced to this moment. The Spirit is said to descend on Jesus in both Matthew and Mark and Luke writes, “Jesus, full of the Holy Spirit, returned from the Jordan and was led about by the Spirit into the wilderness”
John was in every way a fulfillment of Malachi's prophecy and his anointing signified the beginning of Jesus remarkable work of reconciliation.