18 “Anyone who divorces his wife and marries another woman commits adultery, and the man who marries a divorced woman commits adultery.
The Old Testament recognized the reality of divorce, even if it did not explicitly sanction it (Deut. 24:1–4). The rabbis debated legitimate grounds. The conservative school of Shammai allowed a man to divorce his wife only in the case of unfaithfulness, while the more liberal school of Hillel accepted almost any reason, including the ruining of a meal. Rabbi Akiba is even cited as saying that divorce was allowed if the man “found another fairer than she” (m. Gitt. 9:10), giving as justification Deuteronomy 24:1, “[if she] becomes displeasing to him.” Jesus reacts strongly against such a casual attitude toward the law and points to the inviolable nature of marriage: To break a marriage vow and marry another constitutes adultery. God hates divorce (Mal. 2:16).
10 To the married I give this command (not I, but the Lord): A wife must not separate from her husband.
11 But if she does, she must remain unmarried or else be reconciled to her husband. And a husband must not divorce his wife.
Read more from New Bible Commentary
Here Paul distinguishes between a known saying of Jesus, i.e. the Lord (10, 12) as distinct from his own. It must be remembered though that Paul gives clear commands in this section. The Christian wife is not free to separate from her husband. Paul accepts that there are occasions when that is necessary. However, in such circumstances she has only two options i.e. to remain unmarried (lit. separated) or else be reconciled to her husband. The husband is bound by the same strictures which Paul indicates by forbidding the option of divorce. It is presumed that unrepentant immorality is the exception (Mt. 19:9). Both partners being Christians does not ensure their happiness, but it does if they live together in mutual love and respect. All inconsiderate actions not repented of have lasting consequences.
32 But I tell you that anyone who divorces his wife, except for sexual immorality, makes her the victim of adultery, and anyone who marries a divorced woman commits adultery.
Read more from NIV Cultural Backgrounds Study Bible
5:32 except for sexual immorality. One school of Pharisees (the school of Hillel) allowed divorce for any reason; the other (the school of Shammai) allowed it only for “sexual immorality” (as here). A legal divorce permitted remarriage, but without a valid divorce, a wife’s new marriage was invalid, hence adulterous. (In a Jewish legal setting the wife’s divorce was more at issue than the husband’s because Jewish law in principle permitted men to have multiple wives.) Jesus here depicts divorce as invalid, apart from the partner’s infidelity. Because Jesus often used graphic hyperbole (see note on v. 30), offered general statements that might be qualified in some cases (see note on 1Co 7:15), and elsewhere treated the dissolution of marriage as genuine (though normally wrong; cf. Mt 19:6; Jn 4:18), some view the present statement as hyperbole. Hyperbole was meant to graphically reinforce the point, here the warning against breaking one’s marriage.