12 But to the rest I say, and not the Lord; If a brother has a wife who is not a Christian, and it is her desire to go on living with him, let him not go away from her. 13 And if a woman has a husband who is not a Christian, and it is his desire to go on living with her, let her not go away from her husband.
Matthew Henry's Commentary on 1 Corinthians 7:12-13
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.