1 Corinthians 7:10–16

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.

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?

(ESV)