Now when Jesus had finished these sayings, he went away from Galilee and entered the region of Judea beyond the Jordan. And large crowds followed him, and he healed them there. And Pharisees came up to him and tested him by asking, “Is it lawful to divorce one's wife for any cause?” He answered, “Have you not read that he who created them from the beginning made them male and female, and said, ‘Therefore a man shall leave his father and his mother and hold fast to his wife, and the two shall become one flesh’? So they are no longer two but one flesh. What therefore God has joined together, let not man separate.” They said to him, “Why then did Moses command one to give a certificate of divorce and to send her away?” He said to them, “Because of your hardness of heart Moses allowed you to divorce your wives, but from the beginning it was not so. And I say to you: whoever divorces his wife, except for sexual immorality, and marries another, commits adultery.” The disciples said to him, “If such is the case of a man with his wife, it is better not to marry.” But he said to them, “Not everyone can receive this saying, but only those to whom it is given. For there are eunuchs who have been so from birth, and there are eunuchs who have been made eunuchs by men, and there are eunuchs who have made themselves eunuchs for the sake of the kingdom of heaven. Let the one who is able to receive this receive it.”
This account is also found in Mark 10:1-12.
Judea beyond the Jordan - Perea, east of the river, is not part of Judea but with the tetrarchy of Herod Antipas, which extended from the Sea of Galilee almost to the Dead Sea. The events of this chapter took place during the Lord’s final journey to Jerusalem for His death.
for any cause - "The rabbis were divided on what were legitimate grounds for divorce. The followers of Shammai held that a man could not divorce his wife unless he found her guilty of sexual immorality. The followers of Hillel were more lax, allowing divorce for many, including trivial, reasons." (Ryrie)
The Lord responds (vs 4-6) to the Pharisees’ question (v 3) by going back to Genesis 1:27 and 2:-23-24 and showing God’s intent for marriage.
"Rather than aligning Himself with either rabbinical position, Jesus cites the purpose of God in creation that husband and wife should be one flesh—oneness of kinship or fellowship with the body as the medium, causing marriage to be the deepest physical and spiritual unity." (Ryrie)
Have you not read (v 4) — They should have known the answer (and probably did, but didn’t want it).
"The Mosaic Law permitted divorce when a wife proved faithless; but the Rabbinical interpreters after their wont disputed over this enactment. The school of Shammai, adhering to the letter of the Law, held that a wife should not be divorced except for unfaithfulness; whereas the school of Hillel, with a laxity very agreeable to the general inclination, allowed a husband to put away his wife "for every cause" — if he disliked her, if he fancied another woman more, if her cookery were not to his taste. The Pharisees would force Jesus to line up with one side or the other of the theological factions and so alienate a part of the crowd. Or perhaps, knowing already what Jesus thought about such questions, they wished to bring Him again into direct conflict with Herod Antipas. That wicked ruler was living with Herodias in open adultery. John had denounced their sin and lost his own head. If they could get Jesus to denounce openly this Herod and the wicked Herodias, they might succeed in doing away with Him soon. The Mosaic law really permitted divorce only for the cause of unfaithfulness, but the popular conception among the Jews at the time of Jesus was that of the Rabbinical interpreters of the school of Hillel. Woman had become a mere chattel of man, subject to his inhuman and cruel treatment. The Pharisees understood well that if Jesus took the side of Shammai or the stricter view of divorce, He would alienate a greater part of the multitude." (Pentecost)
command - Moses didn’t "command" divorce, he permitted it.
your hardness of heart - "Because the Israelites had disobeyed God’s law of marriage and had married Gentile wives, the line would have been corrupted. If the line were corrupted, Messiah could not come in Abraham’s line. It became necessary then to purify the nation to prevent the corruption of the line. There divorce was permitted. This principle is well illustrated in Ezra 10:2-3, 11-14. Christ thus showed that divorce was not a part of God’s original law of marriage but was introduced because of Israel’s disobedience to the law. Thus the uncleanness of Deuteronomy 24:1 had to do with a corrupted bloodline." (Pentecost)
sexual immorality - Pentecost has an interesting take on this which I think is worth considering (see below). It’s hard to say whether the passage leads to this conclusion because it’s hard to say whether this is what the Lord’s audience would have naturally understood, but in light of other teaching the Bible about divorce, it makes sense to me.
"The Greek word translated 'marital unfaithfulness' [sexual immorality in the NKJV] is not the word for adultery but is the general word for immorality. Christ was referring to the Jewish marriage customs of His day. Marriage was begun by drawing a legal contract between the father of a man and the father of a woman, pledging them to each other. This marriage contract was called a betrothal. The couple were called husband and wife by virtue of that marriage contract. The marriage itself was not completed until at least twelve months after the betrothal contract was drawn up. But they were still referred to as husband and wife. Such was the relationship between Joseph and Mary when the angel announced that Mary would conceive a child. The twelve-month waiting period was deemed necessary because of the low state of morals of that day. That period gave sufficient time to reveal whether the woman was pregnant when the contract was drawn up. The interval also allowed time to see if she would become pregnant by an unfaithful act after being joined by contract to her husband. If the wife proved to be immoral, the marriage need not be completed; the contract could be broken by a divorce. However, so binding was the betrothal contract that it could be broken only by the husband appearing before the judges to accuse the woman of immorality. Thus the contract could be broken. Such was Joseph’s decision when he discovered Mary’s pregnancy (Matthew 1:19). It was in light of this context that Christ granted the exception (Matthew 19:9). If one who was betrothed to a wife found in the betrothal period that she was guilty of fornication, that is, that she was an immoral woman, the marriage need not be consummated; but it had to be dissolved by a divorce. Since the marriage had not been completed, the man was free to marry without becoming an adulterer. Thus Christ utterly repudiated the Pharisaic interpretation of Deuteronomy 24:1-4, and He denied the right of divorce. He appealed to God’s original law of marriage by which a man and woman were inseparably united until that marriage was dissolved by death. Thus the only possibility of divorce allowed by Christ was a cancellation of a marriage contract during the Jewish betrothal period before the marriage had been completed. This evidently was the way the disciples understood our Lord’s instruction. They replied, 'If this is the situation,' that is, if it is not possible for a man to put away his wife after marriage even though she proved to be an immoral and faithless wife, then 'it is better not to marry' (Matthew 19:10). Clearly the disciples saw no possibility of obtaining a divorce with divine approval after marriage had been completed. Because the disciples recognized the low state of society and since it was utterly repugnant to them to be inseparably united to a faithless wife, they concluded it was best not to marry at all. Such a conclusion would not have been drawn if they had understood Christ to permit divorce after marriage." (Pentecost)
adultery - "The Greek word translated 'adultery' refers to the sin of a married individual against his partner. If divorce could dissolve a marriage, a remarriage could not be considered adultery. But since Christ proclaimed it to be adultery, the first marriage must be viewed as still standing in the sight of God." (Pentecost)
it is better not to marry - "The disciples seemed to have understood that Christ was teaching a very restricted meaning of 'immorality' and that He completely disallowed divorce of married persons. In turn, Christ acknowledges that the saying 'it is better not to marry' is valid in some cases, and these are enumerated in verse 12—those congenitally incapable, those made incapable, and those who wish to devote themselves more completely to the service of God (1 Cor 7:7, 8, 26, 32-35). Celibacy is an acceptable option." (Ryrie)
eunuch - broadly, a man who doesn’t have sex. This can be because of a birth defect (first clause); because of surgery (second clause); or, by choice (third clause).
The Lord also spoke on divorce in Matthew 5:31-32. Here is Stam on divorce:
"Few people are aware of the fact that the subject of marriage, divorce and re-marriage also has a dispensational aspect. God’s original instructions regarding marriage (Genesis 2:24) were amended — by God — as time passed and circumstances changed.
Under the Law
"Under the Mosaic Law it was comparatively easy for a man to procure a divorce. In certain cases if he merely did not 'delight' in his wife he could dismiss her (Deuteronomy 21:10-14). Indeed, under the Law it was possible for any man to divorce his wife merely because she found 'no favor in his eyes' because he had found some 'uncleanness' (Lit., something offensive) in her (Deuteronomy 24:1-4. In that case the husband merely had to write 'a bill of divorcement' (stating the reasons why he did not wish to keep her) and then 'give it unto her hand and send her out of his house.'
"It must not be overlooked, however, that the reason for these laws on divorce is clearly given by our Lord in response to the Pharisees’ question, 'Why did Moses then command to give her a writing of divorcement, and to put her away?'
"'He saith unto them, Moses because of the hardness of your hearts suffered you to put away your wives: but from the beginning it was not so' (Matthew 19:8).
Under the Kingdom Program
"Under the program of the kingdom there was only one justification recognized for divorce. This was adultery: 'And I say unto you. Whosoever shall put away his wife,except it be for fornication, and shall marry another, committeth adultery' (Matthew 19:9).
"Unquestionably this has a dispensational significance, for Jehovah was about to divorce His wife, Israel, for adultery, and call her 'Lo-ammi,' 'not My people' (Hosea 1:2, 9). In the light of much Old Testament prophecy and the record of the book of Acts, Jehovah and Israel are now divorced and estranged. But they will be reconciled and reunited when He returns to earth as Israel’s Deliverer at the close of the Great Tribulation (see Isaiah 62:4-5; Zephaniah 3:17; Romans 11:26-27).
Under Grace
"Under the present 'dispensation of the grace of God,' however, there is no Scriptural ground for obtaining a divorce. The command is: 'Let not the wife depart from her husband' (1 Corinthians 7:10), and conversely the husband from his wife (v.11). Realizing the great pressures that sometimes bring on divorces, and recognizing the fact that some will depart from their mates regardless of the Scriptures involved, he continues: 'But and if she depart, let her remain unmarried, or be reconciled to her husband. And [i.e., and likewise] let not the husband put away his wife' (1 Corinthians 7:11).
"Thus the married person who is unhappy and seeking a divorce, should ponder the consequences a thousand times, for the person who obtains a divorce is prohibited by Scripture from ever marrying again.
"We realize that there are technicalities involved as to which party did the 'departing' (i.e., who was really responsible for the divorce), the matter of contesting the divorce suit, the question of the unsaved mate, etc. 1 Corinthians 7 sensibly answers these and other questions, but the basic imperative for the dispensation of grace is clear: Nowhere in Paul’s epistles do we find any justification for departing from one’s mate or for obtaining a divorce. Grace will forgive the erring partner and show him the love of Christ." (Stam)