What does Matthew 14:12 mean?

John the Baptist has been executed, behead, by Herod Antipas, the Jewish tetrarch in Israel over Galilee and Perea. He did so following an impulsive promise made during his own birthday party (Matthew 14:6–8), but John's death still amounted to a state execution. In violation of Jewish law, it was performed by decapitation and happened without a trial.

John was the last of Israel's prophets before the arrival of the Messiah, and his death at the hands of Israel's ruler puts him firmly in the company of those prophets. Many of the messengers sent by God were persecuted or killed by wicked kings (Matthew 23:31; Acts 7:51–52). This incident, while tragic and heartbreaking, also probably confirmed to many people that John was sent from God.

Despite being imprisoned, John still had disciples who were loyal to him and lived by his teaching. At least one of Jesus' disciples had formerly been a disciple of John the Baptist (John 1:35–42), and others continued under John's training even after Jesus began His ministry and John was imprisoned.

Now those disciples come and take John the Baptist's headless body away from the fortress of Herod to give it a proper burial. This may have been a risky act for them to carry out since it associated them with an executed criminal and enemy of Herod. They still did so, and then they reported John's death to Jesus.

That brings Matthew's story back to where he began. When hearing about Jesus' power and fame, Herod declared his superstition that Jesus was John the Baptist raised from the dead (Matthew 14:2). This clearly does not make sense, given that Jesus had been alive and involved in public ministry while John was alive and in Herod's prison. It does suggest Herod carried great guilt and perhaps fear over what he did to John. He believed that John lived on somehow in great power despite being executed.