Expositor's Bible Commentary Commentary Matthew 14:9

"And the king was grieved; but for the sake of his oaths, and of them that sat at meat with him, he commanded it to be given;" — Matthew 14:9 (ASV)

Though grieving because of his oath and his loss of face before his guests if he were to renege on his vow, Herod gave the order. Decapitation was contrary to Jewish law, which also forbade execution without trial. So John died, the last of the OT prophets (11:9, 13) who through persecution became models for Jesus’ disciples (5:11–12).