What does Matthew 3:14 mean?

Jesus has arrived at a place along the Jordan River where John the Baptist is preaching to Israel with the message, "Repent, for the kingdom of heaven is at hand" (Matthew 3:2). John has been baptizing those willing to publicly repent of sin and renew their commitment to live in faithfulness to the Lord.

John recognizes that Jesus is the very Messiah he has been preaching about. We don't know when John discovered this. He may have been taught it as a child, accompanied by his parent's explanation of the circumstances of Jesus' birth (Luke 1—2). In any case, John resists the idea that he should baptize Jesus. He had said of the Messiah, after all, that he was not even worthy to carry His sandals (Matthew 3:11).

As a prophet of God, John had the authority to baptize the people of Israel as a sign of their repentance before God. He could not imagine he had the authority to baptize the Messiah. Also, he likely understood that Jesus had no sin to repent from. Nor would God's Promised One need to declare a change of mind to the people. From John's perspective, there was no point in such a baptism!

John, as a humble man, was aware of his own sinfulness. He declares that he needs to be baptized by Jesus, not the other way around. By this, John may have meant that he wanted Jesus to conduct his own baptism of repentance. Or, perhaps, he wanted Jesus to baptize him with the Holy Spirit and fire as he said the Messiah would do for those who repented (Matthew 3:11).

Jesus explains His insistence on being baptized by John in the following verse.