1 Corinthians 7:12-18

But to the rest I say, not the Lord, that if any brother has a wife who is an unbeliever, and she consents to live with him, he must not divorce her. And a woman who has an unbelieving husband, and he consents to live with her, she must not send her husband away. For the unbelieving husband is sanctified through his wife, and the unbelieving wife is sanctified through her believing husband; for otherwise your children are unclean, but now they are holy. Yet if the unbelieving one leaves, let him leave; the brother or the sister is not under bondage in such cases, but God has called us to peace. For how do you know, O wife, whether you will save your husband? Or how do you know, O husband, whether you will save your wife? Only, as the Lord has assigned to each one, as God has called each, in this manner let him walk. And so I direct in all the churches. Was any man called when he was already circumcised? He is not to become uncircumcised. Has anyone been called in uncircumcision? He is not to be circumcised.