Jesus, in the Sermon on the Mount, tells us that God wants not only right actions, but also a pure heart (Matt. 5:8). Refraining from murder and adultery does not exhaust those particular commandments; Exodus 20:13–14 also forbids lust and unjust anger (Matt. 5:21–30). This is in line with the Old Testament, which says the Law must be followed in heart and in deed (Deut. 6:6; Ps. 37:31).
Jesus’ corrections of the Pharisaic traditions are not an exposition of the Law that covers every single possible situation. For example, Christ says “everyone who is angry with his brother will be liable to judgment” (Matt. 5:22), but He does not mean that anger is always evil, as He Himself will get angry (21:12–13) without sinning (1 Peter 2:22). Ungodly anger is what the injunction against murder forbids. We can (rarely) be righteously angry and yet not sin (Eph. 4:26).
This point helps us understand today’s passage. Jesus does not give every possible ground for divorce when He allows it for “sexual immorality” (Matt. 5:31–32); desertion by an unbelieving spouse also makes divorce permissible (1 Cor. 7:12–16). Moreover, the Greek word for “sexual immorality” in today’s passage (porneia) covers all types of sexual misconduct, implying that some sexual sins besides extramarital affairs can be legitimate grounds for divorce. Yet Jesus is not allowing divorce for any instance of lust or sexual indiscretion. Otherwise, every lewd thought is just cause for divorce. Since no sinner has been fully pure in this area, every marriage would then be dissolvable, which clearly violates our Lord’s high view of holy matrimony ( Matt. 19:1–12).
As with other complicated problems in the Christian life, we go to our pastors and elders to see if a particular form of porneia is legal grounds for divorce. God gives us the church to help us work through complex issues (Acts 15:1–35). Each marriage is different, and choosing the right course of action can be hard, but wise church leaders are to apply Scripture properly and give sound direction.
Divorce is often easier than working through marital problems and is appealing to our fallen nature. We must recognize this lest we adopt the world’s practice of sanctioning divorces for reasons other than those God has given.
John Calvin reminds us that “the bond of marriage is too sacred to be dissolved at the will, or rather at the licentious pleasure, of men.” Many issues can drive spouses to despair and contemplate an unbiblical divorce. That is why we must seek help for our marital troubles at the first sign of trouble. If you need counseling, make an appointment with your pastor today. If you know of another couple who is having problems, encourage them to seek counseling as well.