1 Corinthians 7:10-14

10To the married I give this command (not I, but the Lord): A wife must not separate from her husband.

11But if she does, she must remain unmarried or else be reconciled to her husband. And a husband must not divorce his wife. 12To the rest I say this (I, not the Lord): If any brother has a wife who is not a believer and she is willing to live with him, he must not divorce her. 13And if a woman has a husband who is not a believer and he is willing to live with her, she must not divorce him.

14For the unbelieving husband has been sanctified through his wife, and the unbelieving wife has been sanctified through her believing husband. Otherwise your children would be unclean, but as it is, they are holy.