Our Lord's Sermon on the Mount

³⁹ “It has been said, Whosoever shall put away his wife, let him give her a writing of divorcement.” This is the lesser righteousness of the Pharisees, which is not opposed by what our Lord says: “But I say unto you, That whosoever shall put away his wife, saving for the cause of fornication, causes her to commit adultery: and whosoever shall marry her that is loosed from her husband commits adultery.” For He who gave the commandment that a writing of divorcement should be given, did not give the commandment that a wife should be put away; but “whosoever shall put away,” says He, “let him give her a writing of divorcement,” in order that the thought of such a writing might moderate the rash anger of him who was getting rid of his wife.

And, therefore, He who sought to interpose a delay in putting away, indicated as far as He could to hard-hearted men that He did not wish separation. And accordingly the Lord Himself in another passage, when a question was asked Him as to this matter, gave this reply: “Moses did so because of the hardness of your hearts.” For however hard-hearted a man may be who wishes to put away his wife, when he reflects that, on a writing of divorcement being given her, she could then without risk marry another, he would be easily appeased.

Our Lord, therefore, in order to confirm that principle, that a wife should not lightly be put away, made the single exception of fornication; but enjoins that all other annoyances, if any such should happen to spring up, be borne with fortitude for the sake of conjugal fidelity and for the sake of chastity; and he also calls that man an adulterer who should marry her that has been divorced by her husband. And the Apostle Paul shows the limit of this state of affairs, for he says it is to be observed as long as her husband lives; but on the husband's death he gives permission to marry. For he himself also held by this rule, and therein brings forward not his own advice, as in the case of some of his admonitions, but a command by the Lord when he says: “And unto the married I command, yet not I, but the Lord, Let not the wife depart from her husband: but and if she depart, let her remain unmarried, or be reconciled to her husband: and let not the husband put away his wife.” I believe that, according to a similar rule, if he shall put her away, he is to remain unmarried, or be reconciled to his wife. For it may happen that he puts away his wife for the cause of fornication, which our Lord wished to make an exception of. But now, if she is not allowed to marry while the husband is living from whom she has departed, nor he to take another while the wife is living whom he has put away, much less is it right to commit unlawful acts of fornication with any parties whomsoever. More blessed indeed are those marriages to be reckoned, where the parties concerned, whether after the procreation of children, or even through contempt of such an earthly progeny, have been able with common consent to practise self-restraint toward each other: both because nothing is done contrary to that precept whereby the Lord forbids a spouse to be put away (for he does not put her away who lives with her not carnally, but spiritually), and because that principle is observed to which the apostle gives expression, “It remains, that they that have wives be as though they had none.”