(13) Let her not leave him.—Better, let her not put him away; the Greek being the same as is applied to the husband in 1Corinthians 7:12. Under Roman law—and St. Paul was writing to those who were under such law—the wife, as well as the husband, was permitted to obtain a divorce. It is therefore probable that St. Paul uses the stronger term here in reference to the woman’s action in the matter, instead of repeating the same word as in 1Corinthians 7:10. Some have suggested that the reason St. Paul applies this word to the action of the woman in the matter is that, in the case under consideration, the fact of the wife being a Christian inverts, in St. Paul’s opinion, the natural order, and makes her the superior. This is wholly inadmissible, and quite contrary to St. Paul’s view of the absolute superiority of the " husband. (See 1Corinthians 11:3; Ephesians 5:22; 1Timothy 2:11.)

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, Ro 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.Let her not leave him - A change of phraseology from the last verse, to suit the circumstances. The wife did not have power to "put away" the husband, and expel him from his own home; but she might think it her duty to be separated from him. The apostle counsels her not to do this; and this advice should still be followed. She should still love her husband and seek his welfare; she should be still a kind, affectionate, and faithful wife; and all the more so that she may show him the excellence of religion, and win him to love it. She should even bear much, and bear it long; nor should she leave him unless her life is rendered miserable, or in danger; or unless he wholly neglects to make provision for her, and leaves her to suffering, to want, and to tears. In such a case no precept of religion forbids her to return to her father's house, or to seek a place of safety and of comfort. But even then it is not to be a separation on account of a difference of religious sentiment, but for brutal treatment. Even then the marriage tie is not dissolved, and neither party is at liberty to marry again. 13. the woman—a believer.

let her not leave him—"her husband," instead of "him," is the reading of the oldest manuscripts The Greek for "leave" is the same as in 1Co 7:12, "put away"; translate, "Let her not put away [that is, part with] her husband." The wife had the power of effecting a divorce by Greek and Roman law.

See Poole on "1 Corinthians 7:12"

And the woman which hath an husband that believeth,.... The apostle puts the case both ways, there being the same reason for one as for another; that if she that was a sister, who was partaker of the grace of God, and a member of the church, had a husband to whom she was married before her conversion; who was an unbeliever, had no faith in Christ, nor any notion of the Gospel, but an infidel to both:

and if he be pleased to dwell with her; loves her, and is willing to continue with her; neither puts her away from him, nor departs from her on account of her Christianity:

let her not leave him; but continue, and cohabit with him as man and wife; this is the advice the apostle gives, as agreeably to the light of nature and reason; as becoming the Gospel of Christ, and as what might serve to recommend it, and spread the knowledge of it.

And the woman which hath an husband that believeth not, and if he be pleased to dwell with her, let her not leave him.