But I say unto you, that whosoever shall put away his wife, not for fornication, and shall marry another, commits adultery; and he who marries one put away commits adultery.
The Pharisees came to Jesus with a test: could a man divorce his wife for any reason he liked? His answer took them back past Moses to creation, and then landed on this verse. In one sentence He names the only ground for ending a marriage, and the point at which a second marriage becomes adultery.
"And I say to you" — Christ's own authority
The Pharisees thought Scripture was on their side. They pointed to Moses, who allowed a man to hand his wife a certificate of divorce. That permission was itself evidence against them, and the Lord answers with His own authority:
They did not understand Moses, and they did not understand themselves. Their own argument turns against them in the simplest way: "Because of your hardness of heart Moses allowed you to divorce your wives, but from the beginning it was not so." It was Moses himself who was supplying the evidence — and what evidence — of their own condition! ... And He turns on them with one of those commanding sayings that sweep aside all power of resistance like a lightning flash of truth.
One writer contrasts what Moses allowed with what God's heart is really like:
Moses had allowed this because of the hardness of their hearts, but from the beginning it was not so. How clearly this shows that the law itself was not at all the expression of God's heart! In this case law was more permissive than the grace of God is! For grace enables a person to overcome difficulties in a way that law never could.
Why the exception is not really an exception
The clause "except for sexual immorality" does not open a loophole in a bond that would otherwise hold. It points to a bond already destroyed.
He establishes, or rather re-establishes, the true character of marriage as a bond that cannot be dissolved. I say it cannot be dissolved, because the case of unfaithfulness is not really an exception. The guilty person had already broken the bond. It was no longer man and woman one flesh.
This is also why the innocent party is not the one sinning:
The one exception is allowed because the sin has violated the marriage bond so deeply that it is as good as broken already. If one partner is guilty of sexual immorality, then it would not be adultery for the other to divorce and marry someone else. But the person who marries the partner put away for that sin would be guilty of adultery.
Permission, not instruction
Nothing here tells a wronged partner to divorce. One writer shows both the mercy and the limit:
In His grace He makes room for one possible exception. A marriage can be dissolved before God when the terrible sin of adultery attacks its spiritual, mental and physical unity. This is not a command. It is an exception, in which God meets the wronged partner in his spiritual or emotional weakness. Yet do not forget: the sin of adultery can and should be forgiven when the guilty partner confesses it honestly, and it does not have to lead to divorce.
A legal decree does not end a marriage before God
The weight of the verse falls on the words "and marries another." Adultery lies in the new union, not in the paperwork:
A divorce carried out before men (that is, in a court) does not by itself break the marriage entered into before God and man. What breaks it is the sexual union with another partner afterwards — even when this takes place in a new marriage!
Where the writers differ
All agree that sexual immorality is the one ground stated here. Whether Scripture allows any other ground, they do not all say the same. One writer treats the clause as closing the question:
The Lord Jesus here gives room for one exception, which clearly excludes any other exception... Yet this one and only exception is missing in Mark 10:11-12 and Luke 16:18. Paul in 1 Corinthians 7 does not mention it either... The Lord does not say that divorce cannot be avoided when one partner commits sexual immorality. He says only that in such a case, if the other partner remarries after a divorce, it is not adultery.
Another writer, commenting on the same teaching in Mark, points to a second case:
Often there may have been fault on both sides, and before another marriage a person should be broken before God, seeking only His will. 1 Corinthians 7:15 also shows that desertion breaks the marriage bond, so the deserted partner is left no longer under that bond.
Summary
- Beginning. God's design at creation is the standard, not what Moses allowed. That permission measured hard hearts, not God's mind.
- Bond. Marriage is a bond that cannot be dissolved, so the exception is no loophole. Sexual sin has already broken the one-flesh tie; the divorce only admits it.
- But. Even then God permits divorce; He does not command it. Confession opens the way to forgiveness, and the marriage can stand.
- Beyond paper. A court decree does not undo what God joined. The adultery named here belongs to the new union, and to whoever marries the partner put away.
- Beware. Commentators differ on whether desertion also frees the deserted partner. Anyone in that position should seek only God's will before remarrying.