I should like to show what the man is who insults, what he that practises self-control, and to bring nakedly before you the soul of the one and the other. For you should see the one like a sea tost with a tempest, but the other like a harbor free from disturbance. For it is not disturbed by these evil blasts, but puts them to rest easily. For indeed they who are insulting, do everything in order to make it sting. When then they fail of that hope, even they are thenceforth at peace, and go away amended. For it is impossible that a man, who is angry, should not utterly condemn himself, even as on the other hand it is impossible for one who is not angry to be self-condemned. For though it be necessary to retaliate, it is possible to do this without anger (and it were more easy and more wise than with anger) and to have no painful feeling. For if we be willing, the good things will be from ourselves, and we shall be with the grace of God sufficient for our own safety and honor.
For why do you seek the glory that comes from another? Do thou honor yourself, and no one will be able to insult you; but if you dishonor yourself, though all should honor you, you will not be honored. For like as, unless we put ourselves in an evil state, no one else puts us in such a state; even so unless we insult ourselves, no one else can put us to shame.
For let any man be great and worthy of admiration, and let all men call him an adulterer, a thief, a violater of tombs, a murderer, a robber, and let him be neither provoked or indignant, nor be conscious to himself of any of these crimes, what disgrace will he thence undergo? None. What then, you may say, if many have such an opinion of him? Not even so is he disgraced, but they bring shame upon themselves, by accounting one, who is not such, to be such. For tell me, if any one think the sun to be dark, does he bring an ill name on that heavenly body, or on himself? Surely on himself, getting himself the character of being blind or mad. So also they that account wicked men good, and they that make the opposite error, disgrace themselves.
Wherefore we ought to give the greater diligence, to keep our conscience clear, and to give no handle against ourselves, nor matter for evil suspicion; but if others will be mad, even when this is our disposition, not to care very much, nor to grieve. For he that has got the character of a wicked man, being a good man, is in no degree thereby hurt as regards his being such as he is; but he that has been suspecting another vainly and causelessly, receives the utmost harm; as, on the other hand, the wicked man, if he be supposed to be the contrary, will gain nothing thence, but will both have a heavier judgment, and be led into greater carelessness. For he that is such and is suspected thereof, may perhaps be humbled, and acknowledge his sins; but when he escapes detection, he falls into a state past feeling. For if, while all are accusing them, offenders are hardly stirred up to compunction, when so far from accusing them, some even praise them, at what time will they who are living in vice be able to open their eyes? Do you hear that Paul also blames for this, that the Corinthians (so far from permitting him that had been guilty of fornication, to acknowledge his own sin), applauding and honoring him, did on the contrary urge him on in vice thereby? Wherefore, I pray, let us leave the suspicions of the multitude, their insults and their honors, and let us be diligent about one thing only, that we be conscious to ourselves of no evil thing, nor insult our own selves. For so both here, and in the world to come, we shall enjoy much glory, unto which God grant we all may attain, by the grace and love towards man of our Lord Jesus Christ, to whom be glory world without end. Amen.
Source: Homilies on the Gospel of St. Matthew (New Advent)