3 Wherefore also He subjoins,
“If your right eye offend you, pluck it out, and cast it from you.”
Thus, lest you should say, “But what if she be akin to me? What if in any other way she belong to me?” therefore He has given these injunctions; not discoursing about our limbs—far from it—for nowhere does He say that our flesh is to be blamed for things, but everywhere it is the evil mind that is accused. For it is not the eye that sees, but the mind and the thought. Often, for instance, we being wholly turned elsewhere, our eye sees not those who are present. So that the matter does not entirely depend upon its working. Again, had He been speaking of members of the body, He would not have said it of one eye, nor of the right eye only, but of both. For he who is offended by his right eye, most evidently will incur the same evil by his left also. Why then did He mention the right eye, and add the hand? To show you that not of limbs is He speaking, but of them who are near unto us. Thus, “If,” says He, “you so lovest any one, as though he were in stead of a right eye; if you think him so profitable to you as to esteem him in the place of a hand, and he hurts your soul; cut off even these.” And see the emphasis; for He says not, “Withdraw from him,” but to show the fullness of the separation, “pluck it out,” says He, “and cast it from you.”
Then, forasmuch as His injunction was sharp, He shows also the gain on either hand, both from the benefits and from the evils, continuing in the metaphor.
“For it is profitable for you,” says He, “that one of your members should perish, and not that your whole body should be cast into hell.”
For while he neither saves himself, nor fails to destroy you too, what kindness is it for both to sink, whereas if they were separated, one at least might have been preserved?
But why did Paul then, it may be said, choose to become accursed? Not on condition of gaining nothing, but with a view to the salvation of others. But in this case the mischief pertains to both. And therefore He said not, “pluck out” only, but also “cast from you:” to receive him again no more, if he continue as he is. For so shall you both deliver him from a heavier charge, and free yourself from ruin.
But that you may see yet more clearly the profit of this law; let us, if you please, try what has been said, in the case of the body itself, by way of supposition. I mean, if choice were given, and you must either, keeping your eye, be cast into a pit and perish, or plucking it out, preserve the rest of your body; would you not of course accept the latter? It is plain to everyone. For this were not to act as one hating the eye, but as one loving the rest of the body. This same reckoning do thou make with regard to men also and women: that if he who harms you by his friendship should continue incurable, his being thus cut off will both free you from all mischief, and he also will himself be delivered from the heavier charges, not having to answer for your destruction along with his own evil deeds.
Do you see how full the law is of gentleness and tender care, and that which seems to men in general to be severity, how much love towards man it discloses?
Let them hearken to these things, who hasten to the theatres, and make themselves adulterers every day. For if the law commands to cut off him, whose connection with us tends to our hurt; what plea can they have, who, by their haunting those places, attract towards them daily those even that have not yet become known to them, and procure to themselves occasions of ruin without number?
For henceforth, He not only forbids us to look unchastely, but having signified the mischief thence ensuing, He even straitens the law as He goes on, commanding to cut off, and dissever, and cast somewhere far away. And all this He ordains, who has uttered words beyond number about love, that in either way you might learn His providence, and how from every source He seeks your profit.
4. “Now it has been said, Whosoever shall put away his wife, let him give her a writing of divorcement. But I say unto you, Whosoever shall put away his wife, saving for the cause of fornication, causes her to commit adultery; and whosoever marries her that is put away, commits adultery.”
He goes not on to what lies before Him, until He have well cleared out the former topics. For, lo, He shows us yet another kind of adultery. And what is this? There was an ancient law made, that he who hated his wife, for whatever kind of cause, should not be forbidden to cast her out, and to bring home another instead of her. The law however did not command him simply to do this, but after giving the woman a writing of divorcement, that it might not be in her power to return to him again; that so at least the figure of the marriage might remain.
For if He had not enjoined this, but it were lawful first to cast her out, and take another, then afterwards to take back the former, the confusion was sure to be great, all men continually taking each others' wives; and the matter thenceforth would have been direct adultery. With a view to this, He devised, as no small mitigation, the writing of divorcement.
But these things were done by reason of another, a far greater wickedness; I mean, had He made it necessary to keep in the house her even that was hated, the husband, hating, would have killed her. For such was the race of the Jews. For they who did not spare children, who slew prophets, and “shed blood as water,” much more would they have showed no mercy to women. For this cause He allowed the less, to remove the greater evil. For that this was not a primary law, hear Him saying, “Moses wrote these things according to the hardness of your hearts,” that you might not slay them in the house, but rather put them out. But forasmuch as He had taken away all wrath, having forbidden not murder only, but even the mere feeling of anger, He with ease introduces this law likewise. With this view also He is ever bringing to mind the former words, to signify that His sayings are not contrary to them, but in agreement: that He is enforcing, not overthrowing them; perfecting, not doing them away.
And observe Him everywhere addressing His discourse to the man. Thus, “He that puts away his wife,” says He, “causes her to commit adultery, and he that marries a woman put away, commits adultery.” That is, the former, though he take not another wife, by that act alone has made himself liable to blame, having made the first an adulteress; the latter again has become an adulterer by taking her who is another's. For tell me not this, “the other has cast her out;” nay, for when cast out she continues to be the wife of him that expelled her. Then lest He should render the wife more self-willed, by throwing it all upon him who cast her out, He has shut against her also the doors of him who was afterwards receiving her; in that He says, “He who marries her that is put away commits adultery;” and so makes the woman chaste even though unwilling, and blocks up altogether her access to all, and suffers her not to give an occasion for jealousy. For she who has been made aware that she positively must either keep the husband, who was originally allotted to her, or being cast out of that house, not have any other refuge—she even against her will was compelled to make the best of her consort.
Source: Homilies on the Gospel of St. Matthew (New Advent)