Many commentators dismiss this question by saying that Mark and Luke only give a summary of the Lord’s teaching on divorce, while Matthew supplies the detail. The facts suggest otherwise. Mark, although a brief gospel, supplies considerable details on the matter (Mark 10: 2–12), including details not found in Matthew. Furthermore, if his account is only a summary of the Lord’s teaching, then it is a seriously flawed summary since he omits what is surely fundamental information in any discussion on the justifiable grounds for divorce, (which was, after all, the question put to the Lord). There is a world of difference between a presentation that outlaws divorce absolutely (as in Mark), and one which allows it (as in Matthew)!
The details as the exception clause are omitted in Mark and Luke, not for the sake of brevity, but on account of the readership for which they were writing. Matthew wrote for the Jew (which is why he frequently quotes the OT), and his record of the Lord’s teaching on divorce gives details particularly relevant for them and them only. Mark and Luke write more for the Gentiles. This is why Mark refers to a woman divorcing her husband (Mark 10: 12), while Matthew does not––under Judaism, only a man could initiate divorce proceedings.
It is frequently asserted that marital unfaithfulness is the only grounds given in the NT for divorce. If that is so, why do not Mark and Luke mention it? (Presumably adultery was just as prevalent among the Greeks as among the Jews.) Most of these commentators prefer to ignore the fact that the only practical case of divorce mentioned in the NT is that proposed by Joseph on the grounds (as he supposed) of pre–marital sex on the part of Mary (Matt. 1: 18–20), that is fornication in its specific sense. Mary and Joseph were not married at the time, but betrothed––betrothal being, under Jewish law, a legal contract leading to marriage. The contract was binding unless a legal annulment was obtained. It was incumbent on Joseph, being a “righteous [man]” to “put away” Mary (‘divorce’ is the same word in Greek), in view of what appeared to be immoral behaviour on her part. He thought that she was guilty of fornication.
When the Lord cites “fornication” only a little further on in Matthew (5: 32), as grounds for divorce, there is no reason to suppose that He meant adultery (particularly since He uses different Greek words for adultery and fornication in the same sentence). If He had meant adultery (which is, after all, not an uncommon event) it is difficult to imagine why, in Matthew 19, He would have mentioned it only when pressed (compare vs3–6, and 7–9). Immorality discovered during betrothal, by contrast, would be a comparatively rare event.
In the example given in Matt. 19: 9, we have a man who wrongly divorces his wife (“not for fornication”), and marries another woman. This fresh union, the Lord says, is not marriage, but adultery. Why? Because in the Lord’s eyes he is still married to his first partner––his divorce is invalid. What of that first partner? Can she re–marry? No, says the Lord, for “he who marries one put away commits adultery”. Whoever married her would be committing adultery because she is still married to her first partner. Neither the man’s unrighteous divorce nor his subsequent adultery have annulled his marriage. Though the woman is innocent, and the behaviour of her husband disgraceful, the Lord does not provide her with a way of escape from her marriage––she is not free to re–marry. This conclusion is confirmed by examining Matt. 5: 32. There the man is said to make the woman commit adultery by divorcing her. Why makes her commit adultery? Because in the East the only career open to a woman was marriage. Her divorce means that she must re–marry in order to survive––in that sense her original husband makes her re–marry. The Lord, however, does not call this subsequent union re–marriage but adultery. He regards her as still married to her original partner. She should be re–united to him––she cannot free herself from the marriage.
These facts expose a serious flaw in the argument of those who persist in saying that the exception clause refers to adultery. In Mark, the Lord puts a married man and a married woman on an equal footing with regard to the ability to divorce––He says neither can do it. Yet if the exception clause in Matthew refers to adultery, then in Matthew the married man and his wife are not put on an equal footing. He, it is said, can put away his wife for adultery. The wife, however, as we have seen, cannot escape marriage, even if the husband is adulterous. There is no such contradiction between the two gospels if the exception clause is accepted as relating to betrothal alone. Then, in Matthew as in Mark, the marriage vows are binding on both partners.
