It is not lawful for thee to have her — It was not lawful indeed for either of them to have her. For her father Aristobulus was their own brother. John's words were rough, like his raiment. He would not break the force of truth by using soft words, even to a king.
Related Commentaries of Matthew 14:4
Matthew 14:4
4 For John said unto him, It is not lawful for thee to have her.