Therefore, to avoid this vice we should note that no one is allowed publicly to judge and reprove his neighbor, although he may see him sin, unless he have a command to judge and to reprove. For there is a great difference between these two things, judging sin and knowing sin. You may indeed know it, but you are not to judge it. I can indeed see and hear that my neighbor sins, but I have no command to report it to others. Now, if I rush in, judging and passing sentence, I fall into a sin which is greater than his. But if you know it, do nothing else than turn your ears into a grave and cover it, until you are appointed to be judge and to punish by virtue of your office.
Those, then, are called slanderers who are not content with knowing a thing, but proceed to assume jurisdiction, and when they know a slight offense of another, carry it into every corner, and are delighted and tickled that they can stir up another's displeasure [baseness], as swine roll themselves in the dirt and root in it with the snout. This is nothing else than meddling with the judgment and office of God, and pronouncing sentence and punishment with the most severe verdict. For no judge can punish to a higher degree nor go farther than to say: "He is a thief, a murderer, a traitor," etc. Therefore, whoever presumes to say the same of his neighbor goes just as far as the emperor and all governments. For although you do not wield the sword, you employ your poisonous tongue to the shame and hurt of your neighbor.
God therefore would have it prohibited that any one speak evil of another even though he be guilty, and the latter know it right well; much less if he do not know it, and have it only from hearsay. But you say: Shall I not say it if it be the truth? Answer: Why do you not make accusation to regular judges? Ah, I cannot prove it publicly, and hence I might be silenced and turned away in a harsh manner [incur the penalty of a false accusation]. "Ah, indeed, do you smell the roast?" If you do not trust yourself to stand before the proper authorities and to make answer, then hold your tongue. But if you know it, know it for yourself and not for another. For if you tell it to others, although it be true, you will appear as a liar, because you cannot prove it, and you are, besides acting like a knave. For we ought never to deprive any one of his honor or good name unless it be first taken away from him publicly.
False witness, then, is everything which cannot be properly proved. Therefore, what is not manifest upon sufficient evidence no one shall make public or declare for truth; and in short, whatever is secret should be allowed to remain secret, or, at any rate, should be secretly reproved, as we shall hear. Therefore, if you encounter an idle tongue which betrays and slanders some one, contradict such a one promptly to his face, that he may blush thus many a one will hold his tongue who else would bring some poor man into bad repute from which he would not easily extricate himself. For honor and a good name are easily taken away, but not easily restored.
Thus you see that it is summarily forbidden to speak any evil of our neighbor, however the civil government, preachers, father and mother excepted, on the understanding that this commandment does not allow evil to go unpunished. Now, as according to the Fifth Commandment no one is to be injured in body, and yet Master Hannes [the executioner] is excepted, who by virtue of his office does his neighbor no good, but only evil and harm, and nevertheless does not sin against God's commandment, because God has on His own account instituted that office; for He has reserved punishment for His own good pleasure, as He threatens in the First Commandment, — just so also, although no one has a right in his own person to judge and condemn anybody, yet if they to whose office it belongs fail to do it, they sin as well as he who would do so of his own accord, without such office. For here necessity requires one to speak of the evil, to prefer charges, to investigate and testify; and it is not different from the case of a physician who is sometimes compelled to examine and handle the patient whom he is to cure in secret parts. Just so governments, father and mother, brothers and sisters, and other good friends, are under obligation to each other to reprove evil wherever it is needful and profitable.
But the true way in this matter would be to observe the order according to the Gospel, Matt. 18, 15, where Christ says: If thy brother shall trespass against thee, go and tell him his fault between thee and him alone. Here you have a precious and excellent teaching for governing well the tongue, which is to be carefully observed against this detestable misuse. Let this, then, be your rule, that you do not too readily spread evil concerning your neighbor and slander him to others, but admonish him privately that he may amend [his life]. Likewise, also, if some one report to you what this or that one has done, teach him, too, to go and admonish him personally if he have seen it himself; but if not, that he hold his tongue.
The same you can learn also from the daily government of the household. For when the master of the house sees that the servant does not do what he ought, he admonishes him personally. But if he were so foolish as to let the servant sit at home, and went on the streets to complain of him to his neighbors, he would no doubt be told: "You fool, what does that concern us? Why do you not tell it to him ?" Behold, that would be acting quite brotherly, so that the evil would be stayed, and your neighbor would retain his honor. As Christ also says in the same place: If he hear thee, thou host gained thy brother. Then you have done a great and excellent work; for do you think it is a little matter to gain a brother? Let all monks and holy orders step forth, with all their works melted together into one mass, and see if they can boast that they have gained a brother.
Further, Christ teaches: But if he will not hear thee, then take with thee one or two more, that in the mouth of two or three witnesses every word may be established. So he whom it concerns is always to be treated with personally, and not to be spoken of without his knowledge. But if that do not avail, then bring it publicly before the community, whether before the civil or the ecclesiastical tribunal. For then you do not stand alone, but you have those witnesses with you by whom you can convict the guilty one, relying on whom the judge can pronounce sentence and punish. This is the right and regular course for checking and reforming a wicked person. But if we gossip about another in all corners and stir the filth, no one will be reformed, and afterwards when we are to stand up and bear witness, we deny having said so. Therefore it would serve such tongues right if their itch for slander were severely punished, as a warning to others. If you were acting for your neighbor's reformation or from love of the truth, you would not sneak about secretly nor shun the day and the light.
All this has been said regarding secret sins. But where the sin is quite public so that the judge and everybody know it you can without any sin avoid him and let him go, because he has brought himself into disgrace, and you may also publicly testify concerning him. For when a matter is public in the light of day, there can be no slandering or false judging or testifying; as, when we now reprove the Pope with his doctrine, which is publicly set forth in books and proclaimed in all the world. For where the sin is public, the reproof also must be public, that every one may learn to guard against it.
Thus we have now the sum and general understanding of this commandment, to wit, that no one do any injury with the tongue to his neighbor, whether friend or foe, nor speak evil of him, no matter whether it be true or false, unless it be done by commandment or for his reformation, but that every one employ his tongue and make it serve for the best of every one else, to cover up his neighbor's sins and infirmities, excuse them, palliate and garnish them with his own reputation. The chief reason for this should be the one which Christ alleges in the Gospel, in which He comprehends all commandments respecting our neighbor, Matt. 7, 12: Whatsoever ye would that men should do to you, do ye even so to them.