1 Corinthians 7:14-16 “For the unbelieving husband is sanctified by the wife, and the unbelieving wife is sanctified by the husband: else were your children unclean; but now are they holy. But if the unbelieving depart, let him depart. A brother or a sister is not under bondage in such cases: but God hath called us to peace. For what knowest thou, O wife, whether thou shalt save thy husband? or how knowest thou, O man, whether thou shalt save thy wife?”
We know that understanding who Jesus Christ truly is cannot be passed from one person to another. Jesus plainly told Peter that the truth of who He is could not be revealed by flesh and blood (Mat 16:17). This revelation can only come from God the Father. Neither can a husband or wife put away the sins of the other; only Jesus can save His people from their sins (Mat 1:21).
According to Gill’s commentary, the sanctification under consideration here refers to the legality of the actual marriage union. We see this thought carried over even to religious marriage ceremonies today as the phrase is often used of “joining these two people together in holy (sanctified) matrimony.” If Paul is here comparing the unbeliever as a Gentile and the believer as being of God’s chosen people, then the legal custom taught would say this was not a lawful union and should not be recognized.
Furthermore, the children produced by a marriage between a Gentile (unbeliever) and a Jew (as representing God’s covenant people) were not considered to be legitimate. By custom, then, it would have made sense that the union between a believer and an unbeliever would not be a legitimate (sanctified) espousal. Paul is here preserving the family structure that is in place by calling on the Corinthian brethren to take a higher view of this type of union.
As long as the husband and wife can dwell together in peace, Paul says the union should stand. The two being one flesh in marriage, the believing spouse serves to sanctify in the marriage the unbeliever. Since the union stands as sanctified through the believing spouse, then the children are legitimate to the union. Divorce should not be a foregone conclusion in such a union.
On the other hand, Paul makes it very clear that if the unbeliever depart, then let him (or her) go. Our first responsibility in all things is to God. Further, the believing spouse is not under any legal bondage to this union if the unbeliever leaves, because God has called the believer to peace.
Finally, we should always wait on the Lord and trust the leadership of the Holy Spirit. While we know that we cannot save our spouse in the eternal sense, we do not know but what God may use the example of our faithful lives to teach and instruct the unbelieving spouse. Our believing example might only move them to a better standard of living in a moral sense or they might be quickened by the Holy Ghost at some later time and be a great blessing to the union having seen our example of faith.
May we always wait on the Lord to show us His will, and then walk in it knowing that He is our true sanctification in all things!