Matthew 19:7-9

7The Pharisees said to Him, “Why then did Moses command us to give her a certificate of divorce and send her away?”

8He said to them, “Because your hearts were hard and stubborn Moses permitted you to divorce your wives; but from the beginning it has not been this way.

9I say to you, whoever divorces his wife, except for sexual immorality, and marries another woman commits adultery.”