Matthew 19v7-9

Heavenly father
give us grace today not to have a hard heart.

⁷ They asked him, “Why then did Moses command us to give her a certificate of divorce and divorce her?”
⁸ He said to them, “Moses, because of the hardness of your hearts, allowed you to divorce your wives, but from the beginning it has not been so. 
⁹ I tell you that whoever divorces his wife, except for sexual immorality, and marries another, commits adultery;
and he who marries her when she is divorced commits adultery.”