Matthew 19:5-9

and ‘For this reason a man will leave his father and mother and live with his wife. And the two will become one flesh.’ From then on, they are no longer two, but united as one. So what God unites let no one divide!” They responded, “So then why did Moses command us to give a certificate of divorce and it would be lawful?” Jesus said, “Moses permitted you to divorce because your hearts are so hard and stubborn, but originally there was no such thing. But I say to you, whoever leaves his wife for any reason other than immorality, then takes another wife is living in adultery. And whoever takes a divorced woman in marriage is also living in adultery.”