“But to the rest I, not the Lord say: If any brother has a wife who does not believe, and she is willing to live with him, let him not divorce her. And a woman who has a husband who does not believe, if he is willing to live with her, let her not divorce him” (1 Corinthians 7:12-13).
Paul had received questions from the brethren at Corinth (1 Corinthians 7:1 cf. 7:10; 7:12; 7:25; 8:1; 12:1; 16:1-2; 16:12). We have his answers. We do not have the wording of the original questions.
“What about Christians who are married to non-Christians? What about those who have become Christians, who now find themselves married to non-Christians? What about those who have been unable to convert their mates?” It seems that they asked something like this.
Paul answered: (1) A Christian man is not to divorce his non-Christian wife, of she is willing to live with him (and his Christianity). (2) A Christian woman is not to divorce her non-Christian husband, if he is willing to live with her (and her Christianity). The answer is the same for both the Christian man and the Christian woman.
What does Paul mean when he says, ‘I, not the Lord, say…’? Consider this: Paul earlier said, “I command, yet not I but the Lord…” (1 Corinthians 7:10). He did not mean that he was not speaking on this subject. He certainly was speaking on this subject. He was reminding them of what Jesus had taught while on earth. Likewise, when he says, “I, not the Lord, say…” he does not mean that the Lord is not also speaking. Paul is an inspired man. He later writes, “…the things which I write to you are the commandments of the Lord” (1 Corinthians 14:37). The meaning is: He is simply not appealing to what Jesus had taught while on earth. J.W. McGarvey comments, not the Lord “with his own lips” (McGarvey, Thessalonians, Corinthians, Galatians and Romans, p. 80). Adam Clark comments, “The directions which I am now about to give there is no written testimony, and I deliver them now for the first time. These words do not intimate that the apostle was not now under the influence of the Divine Spirit; but that there was nothing in the sacred writings which bore directly on this point.” Guy N. Woods comments, “He is not contrasting the Lord’s authority with his own; he is distinguishing between an express declaration of the Lord while he was on earth, touching the matter and another aspect of the subject on which the Lord did not directly speak” (Woods, Questions and Answers, Vol. 1, p. 87). Robert Dodson comments, “Jesus did not teach these things while in the flesh, probably because it would only confuse people to speak of a situation that did not yet exist. This does not mean, that what Jesus did teach in the flesh, or the teaching of verse 10-11, does not apply to Christians married to non-Christians. Paul’s additional teaching here, to the Christians married to non-Christians is not contradictory, but in harmony with all other inspired teaching on the subject” (Dodson, Brown Trail School of Preaching, class notes on 1 Corinthians).
Why did Paul use this wording? I can think of a couple of possible reasons. (1) It is possible, though I cannot prove it, that Paul’s wording is based on the wording of their question(s). They may have asked, “Paul, what did Jesus teach on this?” (2) The wording of verse 12 is based on the wording of verse 10. It may be that he words things as he does in verse 10 simply to remind then of what Jesus had taught. Jesus set forth instructions about marriage in general. Paul moves from the general (verses 10-11), to the specific situation of a Christian married to a non-Christian (verses 12-16). Kerry Duke comments, “Jesus dealt with this situation generally; Paul addressed the situation specifically” (Duke, The Remarriage of a Divorced Couple, p. 50).
“For the unbelieving husband is sanctified by the wife, and the unbelieving wife is sanctified by the husband; otherwise your children would be unclean; but now they are holy” (1 Corinthians 7:14).
This explains why a Christian in a religiously mixed marriage should stay married (if the non-Christian is willing to live with the Christian). The non-Christian is sanctified and the children are holy.
What does this mean? Here are some theories: (1) Some have thought that this refers to salvation by relationship. However, this view should be rejected (cf. Ezekiel 18:20; John 3:5). It does not fit the immediate context (i.e. 1 Corinthians 7:16). (2) Some have thought that this means that the marriage is legitimate, if at least one of the partners in marriage is a Christian. However, this view should be rejected (cf. Genesis 1:27-28; 2:24; Matthew 19:4-6). Marriage pre-dates Christianity. Marriage pre-dates Judaism. It was created in the beginning. (3) Some have thought that this is referring to the Christian’s sanctifying influence in the home. This is possible. Peter writes of how a Christian wife could win her husband to Christ (1 Peter 3:1-6). Furthermore, A Christian mother can have great influence over her children (2 Timothy 1:5; 3:15). (4) I think that this refers to the fact that the marriage is a legitimate marriage. Otherwise, the children would be illegitimate (cf. 1 Corinthians 7:14). Bill Jackson comments, “He is speaking of the sacredness of the marriage relationship” (Jackson, A Commentary on First Corinthians, p. 63). The situation may not be the best situation, but it is a legitimate marriage.
The best thing one can do, when in a marriage to a non-Christian, is to continue to truly live the Christian life. Be serious about it (if you do not take it seriously why should your mate?). Exemplify it. Let your mate see the beauty of true Christianity ( cf. 1 Peter 3:1-6).