Mark saith, Mark 6:17, for he had married her. Whether this Philip was Herod's brother both by father and mother, is argued by some, as also whether he married her during the life of his brother: the Scripture satisfieth us not in these things, but it is most probable that Philip was his own brother, and that he at least lived in adultery with her during the life of her husband, contrary to the express law of God, Leviticus 18:16.
Related Commentaries of Matthew 14:3
Matthew 14:3
3 For Herod had laid hold on John, and bound him, and put him in prison for Herodias' sake, his brother Philip's wife.