John the prophet
As John's disciples were leaving, Jesus began to speak to the crowd about John:
"What did you go out into the desert to see? A reed swayed by the wind? If not, what did you go out to see? A man dressed in fine clothes? No, those who wear fine clothes are in kings' palaces.
Then what did you go out to see? A prophet? Yes, I tell you, and more than a prophet. This is the one about whom it is written: "I will send my messenger ahead of you, who will prepare your way before you."
I tell you the truth: Among those born of women there has not risen anyone greater than John the Baptist; yet he who is least in the kingdom of heaven is greater than he.
From the days of John the Baptist until now, the kingdom of heaven has been forcefully advancing, and forceful men lay hold of it. For all the Prophets and the Law prophesied until John. And if you are willing to accept it, he is the Elijah who was to come."
Who was Elijah?
Elijah was a prophet when Ahab was king of Israel. Elijah did not experience death, but was taken into heaven in a fiery chariot. He later appeared with Moses in the transfiguration.
Malachi prophesied that Elijah would be sent to Israel hundreds of years later. Jesus showed the disciples that Malachi's prophecy referred to John the Baptist.
2nd Kings 2:9-17