It is my belief, that the whole passage of Matthew 19:3-12 is constructed as a discussion of the much debated passage of Deuteronomy 24:1-4. I believe that the wording “except” in Matthew 19:9 is a mistranslation since the original greek says “mey epi inappropriate contenteia”, which translates as “not over inappropriate contenteia”. In my understanding, there were 2 kinds of validation for divorce in rabbinic teaching, (1) the sexual ones, which required a death penalty on the incontinent spouse, and (2) the non-sexual ones, using Deuteronomy 24:1-4 for their blueprint.
So when Jesus says “not over fornication” in Matthew 19:9, he is not suddenly introducing an “exception” into the debate, he is simply referring to Deuteronomy 24:1-4 using different language. So in effect he says, whosoever divorces his wife using arguments based on Deuteronomy 24:1-4, and marries another, is committing adultery. This means that the first marriage has NOT been ended by the divorce paper, and the man is still married to his first wife. Also, his cohabiting with the new woman is an act of adultery, an ongoing act for that.
So to reiterate my main point: “not over fornication” is simply a technical term to distinguish different kinds of divorce. It does not introduce an exception.
I know there has been a lot of discussion on this, but let me add a little dialog.
When the Pharisees came to Jesus with this question, we know from the text they were trying to tempt him. In my opinion, they were trying to put division between what Moses allowed for the people regarding divorce, verses the stance Jesus had on marriage and divorce.
But Jesus cut them into pieces using the Law of Moses. When Jesus said, except it be for fornication, he was not speaking to them regarding Deuteronomy 24:1-4. This is the passage that the Pharisees were using to tempt him.
The passage Jesus was referring to was earlier in the book. Jesus was not telling them that it was OK to put your wife away for adultery. He was speaking of "fornication". Fornication (even during the times of Jesus) was defined as sexual relations before marriage. A married person cannot commit fornication.
Therefore, what Jesus was telling them was exactly what was commanded by the Law of Moses. And he gave no other exceptions.
The circumstances of the exception is this: As defined by Deuteronomy 22:13-21. In laymen terms, if a man is espoused to a woman and he is under the impression that she is a virgin. Then he takes her in marriage to be his wife. When the couple consummate the marriage and upon doing so, the man discovers that she indeed is not a virgin at all. If he chooses to divorce her on these grounds, then he can put her away in divorce, for fornication.
Now here is the protection for the woman, as written by the Law. If the father and mother of the woman brings the token of their daughters virginity before the elders of the city (the token in this case is the virgins blood on the linens or sheets).
If the token is present, then the man is not permitted to put her away and he is punished.
If the token is not present, then the man can put his wife away for fornication. Then the woman is taken out of the city to be stoned.
Matthew 19:9
And I say unto you, Whosoever shall put away his wife, except it be for fornication, and shall marry another, committeth adultery: and whoso marrieth her which is put away doth commit adultery.
Deuteronomy 22
13 If any man take a wife, and go in unto her, and hate her,
14 And give occasions of speech against her, and bring up an evil name upon her, and say, I took this woman, and when I came to her, I found her not a maid:
15 Then shall the father of the damsel, and her mother, take and bring forth the tokens of the damsel's virginity unto the elders of the city in the gate:
16 And the damsel's father shall say unto the elders, I gave my daughter unto this man to wife, and he hateth her;
17 And, lo, he hath given occasions of speech against her, saying, I found not thy daughter a maid; and yet these are the tokens of my daughter's virginity. And they shall spread the cloth before the elders of the city.
18 And the elders of that city shall take that man and chastise him;
19 And they shall amerce him in an hundred shekels of silver, and give them unto the father of the damsel, because he hath brought up an evil name upon a virgin of Israel: and she shall be his wife; he may not put her away all his days.
20 But if this thing be true, and the tokens of virginity be not found for the damsel:
21 Then they shall bring out the damsel to the door of her father's house, and the men of her city shall stone her with stones that she die: because she hath wrought folly in Israel, to play the harlot in her father's house: so shalt thou put evil away from among you.