12 For the rest of you who are in mixed marriages - Christian married to nonChristian - we have no explicit command from the Master. So this is what you must do. If you are a man with a wife who is not a believer but who still wants to live with you, hold on to her. 13 If you are a woman with a husband who is not a believer but he wants to live with you, hold on to him. 14 The unbelieving husband shares to an extent in the holiness of his wife, and the unbelieving wife is likewise touched by the holiness of her husband. Otherwise, your children would be left out; as it is, they also are included in the spiritual purposes of God. 15 On the other hand, if the unbelieving spouse walks out, you've got to let him or her go. You don't have to hold on desperately. God has called us to make the best of it, as peacefully as we can.
Matthew Henry's Commentary on 1 Corinthians 7:12-15
Commentary on 1 Corinthians 7:10-16
(Read 1 Corinthians 7:10-16)
Man and wife must not separate for any other cause than what Christ allows. Divorce, at that time, was very common among both Jews and Gentiles, on very slight pretexts. Marriage is a Divine institution; and is an engagement for life, by God's appointment. We are bound, as much as in us lies, to live peaceably with all men, Romans 12:18, therefore to promote the peace and comfort of our nearest relatives, though unbelievers. It should be the labour and study of those who are married, to make each other as easy and happy as possible. Should a Christian desert a husband or wife, when there is opportunity to give the greatest proof of love? Stay, and labour heartily for the conversion of thy relative. In every state and relation the Lord has called us to peace; and every thing should be done to promote harmony, as far as truth and holiness will permit.