Matthew 11:7-19
After Jesus is done explaning that he is the Messiah, he explains who John is: The profit Elijah. Jesus quotes Malachi 3
1“Behold, I am going to send My messenger, and he will clear the way before Me And the Lord, whom you seek, will suddenly come to His temple; and the messenger of the covenant, in whom you delight, behold, He is coming,” says the LORD of hosts. (Malachi 3:1).
Finally Jesus showed the hypocracy of the leaders saying John was mad and had a demon because he didn’t eat and drink (remember the bag of locusts he carried for food), and saying Jesus was gluttonous and a drukard because he ate and drank.