1 Corinthians 7:10–11
10 To the married I give this charge (not I, but the Lord): the wife should not separate from her husband 11 (but if she does, she should remain unmarried or else be reconciled to her husband), and the husband should not divorce his wife.
3 And Pharisees came up to him and tested him by asking, “Is it lawful to divorce one’s wife for any cause?” 4 He answered, “Have you not read that he who created them from the beginning made them male and female, 5 and said, ‘Therefore a man shall leave his father and his mother and hold fast to his wife, and the two shall become one flesh’? 6 So they are no longer two but one flesh. What therefore God has joined together, let not man separate.”
7 They said to him, “Why then did Moses command one to give a certificate of divorce and to send her away?” 8 He said to them, “Because of your hardness of heart Moses allowed you to divorce your wives, but from the beginning it was not so. 9 And I say to you: whoever divorces his wife, except for sexual immorality, and marries another, commits adultery.”
1 Corinthians 7:12–16
12 To the rest I say (I, not the Lord) that if any brother has a wife who is an unbeliever, and she consents to live with him, he should not divorce her. 13 If any woman has a husband who is an unbeliever, and he consents to live with her, she should not divorce him. 14 For the unbelieving husband is made holy because of his wife, and the unbelieving wife is made holy because of her husband. Otherwise your children would be unclean, but as it is, they are holy. 15 But if the unbelieving partner separates, let it be so. In such cases the brother or sister is not enslaved. God has called you to peace. 16 For how do you know, wife, whether you will save your husband? Or how do you know, husband, whether you will save your wife?