For John said to Herod, It is not lawful for thee to have the wife of thy brother.

For John had repeatedly told Herod, "You have no right to be living with your brother's wife."

For John said to Herod, It is wrong for you to have your brother's wife.

For John had said unto Herod,.... He had been personally with him, and had plainly and freely told him of his sin, and faithfully reproved him for it; alleging what he had done was contrary to the law of God:
it is not lawful, for thee to have thy brother's wife: See Gill on Matthew 14:4.

For John had said unto Herod, It is not lawful for thee to have thy brother's wife--Noble fidelity! It was not lawful because Herod's wife and Herodias husband were both living; and further, because the parties were within the forbidden degrees of consanguinity (see Leviticus 20:21); Herodias being the daughter of Aristobulus, the brother of both Herod and Philip [JOSEPHUS, Antiquities, 18.5,4].