Matthew 19:5-8

And he said, “‘This explains why a man leaves his father and mother and is joined to his wife, and the two are united into one.’ Since they are no longer two but one, let no one split apart what God has joined together.” “Then why did Moses say in the law that a man could give his wife a written notice of divorce and send her away?” they asked. Jesus replied, “Moses permitted divorce only as a concession to your hard hearts, but it was not what God had originally intended.