In the gospels, Jesus says whoever divorces his wife, except for sexual immorality, and marries another commits adultery, and whoever marries her who has been divorced commits adultery.
No Man Can Part What God has Joined
First, it is important to understand that once a man and woman are married — that is, once God has joined the man and woman and the two become one flesh — they remain married and inseparable until one of them dies. There is no exception, because impotent man lacks the ability to part what the omnipotent God has joined.1
6 So that they are no longer two but one flesh. Therefore, what God has joined together, no man separate!
Ϛʹ ὥστε οὐκέτι εἰσὶν δύο ἀλλὰ σὰρξ μία· ὃ οὖν ὁ θεὸς συνέζευξεν ἄνθρωπος μὴ χωριζέτω
The Greek «ἄνθρωπος μὴ χωριζέτω» is a third-person imperative, expressing a negative command (prohibition), not a subjunctive, expressing a desire or wish. The impossibility originates not solely from the prohibition, but from the fact that it is impossible for man to oppose God’s will.2
Marriage is a covenant, and only upon the death of one of the parties of the covenant is the covenant abolished.
The apostle Paul wrote,3
2 For the married woman is bound by law to her husband as long as he is alive; but if her husband dies, she is released from the law concerning the husband. 3 So then, if while her husband is alive she gives herself to another man, she will be called an adulteress; but if her husband dies, she is free from the law, so that she is not an adulteress if she gives herself to another man. NASB, ©2020
The Exception Clause in the Gospel of Matthew
The Gospel of Matthew contains the only occurrence of the so-called exception clause for divorce. It essentially states that whoever divorces his wife, “except for πορνείᾳ”, and marries another woman commits adultery. The reason why Matthew, unlike Mark or Luke,4 mentions the exception «εἰ μὴ ἐπὶ πορνείᾳ» is because only in the Gospel of Matthew does the very example of the exemption occur — which example the hearer or reader would have recalled.
In the first chapter of Matthew, the author relates how Joseph and Mary were espoused.5 This “betrothal” or ארוסין (erusin) is a Jewish norm in which the man and woman are legally considered married6 but have yet to cohabitate and consummate the marriage. While espoused, the woman still lives in her father’s home.7
While espoused, Joseph discovered that Mary was pregnant.8 Assuming the child was not his and that Mary had intercourse with another man, Joseph intended to divorce Mary9 — for πορνείᾳ.10
The Greek Verb ἐκπορνεῦσαι
In Deut. 22, Moses describes how a man who espoused a woman goes to consummate his marriage with her, but when he does, he discovers that she is not a virgin, because the signs of her virginity are absent.
20 “But if the thing is true, and evidences of virginity are not found for the young woman, 21 then they shall bring out the young woman to the door of her father’s house, and the men of her city shall stone her to death with stones, because she has done a disgraceful thing in Israel, to play the harlot in her father’s house. So you shall put away the evil from among you. NKJV, ©1982
Κʹ ἐὰν δὲ ἐπ᾽ ἀληθείας γένηται ὁ λόγος οὗτος καὶ μὴ εὑρεθῇ παρθένια τῇ νεάνιδι ΚΑʹ καὶ ἐξάξουσιν τὴν νεᾶνιν ἐπὶ τὰς θύρας οἴκου πατρὸς αὐτῆς καὶ λιθοβολήσουσιν αὐτὴν οἱ ἄνδρες τῆς πόλεως αὐτῆς ἐν λίθοις καὶ ἀποθανεῖται ὅτι ἐποίησεν ἀφροσύνην ἐν υἱοῖς Ισραηλ ἐκπορνεῦσαι τὸν οἶκον τοῦ πατρὸς αὐτῆς καὶ ἐξαρεῖς τὸν πονηρὸν ἐξ ὑμῶν αὐτῶν
This is the same scenario that occurred with Mary and Joseph. There was [supposed] evidence that the betrothed woman was not a virgin. Consequently, the man intended to divorce her while betrothed. There is a key relationship between the noun πορνείᾳ11 of Matt. 19:6 and the verb ἐκπορνεῦσαι12 of Deu. 22:21, as will be demonstrated below by Gen. 38:24.
Another example of the relationship between πορνείᾳ and ἐκπορνεῦσαι occurs in Gen. 38:24. In the example of Tamar, she was accused of «ἐκπεπόρνευκεν» (like ἐκπορνεῦσαι, a conjugation of ἐκπορνεύω) and the child with which she was pregnant was said to be «ἐκ πορνείας» (like πορνείᾳ, a declension of πορνεία).
24 And it came to pass, about three months after, that Judah was told, saying, “Tamar your daughter-in-law has played the harlot; furthermore she is with child by harlotry.” So Judah said, “Bring her out and let her be burned!” NKJV, ©1982
ΚΔʹ ἐγένετο δὲ μετὰ τρίμηνον ἀπηγγέλη τῷ Ιουδα λέγοντες ἐκπεπόρνευκεν Θαμαρ ἡ νύμφη σου καὶ ἰδοὺ ἐν γαστρὶ ἔχει ἐκ πορνείας εἶπεν δὲ Ιουδας ἐξαγάγετε αὐτήν καὶ κατακαυθήτω
This demonstrates that πορνεία is a result of the action ἐκπορνεύω. With respect to Matt. 19:6, when the Lord Jesus Christ said that the man was not permitted to divorce the wife except for πορνείᾳ, this means that divorce was permitted when the the wife committed ἐκπορνεύω. As both Deut. 22:21 and Gen. 38:24 demonstrate, ἐκπορνεύω occurs when the espoused wife has sexual intercourse with someone other than her husband while they are espoused.
Joined — The Two Become One Flesh
Although they were legally married, Mary and Joseph had not yet cohabited and consummated the marriage. Therefore, they were not yet joined by God. That is, the two had not become one flesh.
The apostle Paul described that man and woman are joined by sexual intercourse, and consequently, the man and woman become one flesh.13
16 Or do you not know that he who is joined to a harlot is one body with her? For “the two,” He says, “shall become one flesh”.
Although he uses the example of a man and a harlot, the same still applies to any man and woman. Sexual intercourse is the act by which the man and woman are joined in union, as is evident by the apostle Paul’s reference to Gen. 2:24.14 In the case of Mary and Joseph, they were not yet joined by sexual intercourse, therefore Joseph was permitted to divorce Mary because of her supposed infidelity while betrothed.
In summary, the exception clause in Matt. 19:6 pertains to divorce while espoused due to infidelity on the part of the espoused woman. After a man and woman consummate their marriage by sexual intercourse, they are joined by God, and divorce is impossible.
In many cases regarding divorce and remarriage, people who support remarriage after adultery tend to say, "If your ex husband marries another woman, he commits adultery and thus frees you up to be remarried biblically."
Actually, the Bible is quite clear: a married man cannot commit adultery unless he has sexual intercourse with another married man’s wife. If a married man has sexual intercourse with an unmarried woman, including marrying [another unmarried] woman, it is not adultery, as is clear in the case of Abraham, Jacob, David, and multitude of other biblical patriarchs who all had more than one wife and were not guilty of adultery. In the Bible — or at least the Tanakh — women can only have one husband; a man can have multiple wives.
|1 Matt. 19:6; Mark 10:9
2 Isa: 14:24, 14:27
3 Rom. 7:2
4 Mark 10:11; Luke 16:18
5 Matt. 1:18
6 Deu. 22:23 mentions a נַעֲרָ בְתוּלָה מְאֹרָשָׂה לְאִישׁ — “a virgin maiden betrothed to a man” and in the very next verse refers to the same woman as אֵשֶׁת רֵעֵהוּ — “his neighbor’s wife”. This indicates that a betrothed woman was legally considered a man’s wife although the man and woman had not yet consummated their marriage.
7 Jewish Encyclopedia, Vol. 3, pp. 125–126. Also, Moshe ben Maimon, Mishneh Torah, Sefer Nashim, Hilkhot Ishut, Ch. 1, Halakha 3: “Once this process of acquisition has been formalized and a woman has become mekudeshet, she is considered to be married even though the marriage bond has not been consummated and she has not entered her husband's home”. (Translation Eliyahu Touger)
8 Matt. 1:18
9 Matt. 1:19
10 The narrative does not explicitly state Joseph intended to divorce her for πορνείᾳ, but the context demands such explanation.
11 lemma πορνεία
12 lemma ἐκπορνεύω
13 1 Cor. 6:16 cf. Gen. 2:2
14 cf. Moshe ben Maimon, Mishneh Torah, Sefer Nashim, Hilkhot Ishut, Ch. 3, Halakha 5: “If he married (sanctified) [the woman] by sexual intercourse...and when he finishes his sexual intercourse, she will be married (sanctified)”.