Halakhah zu Mischlej 21:2

And now we return to what we began with. For from what we wrote in the beginning [sections 3 and 4], we learn that it is forbidden to demean one's friend and to tell of his negative traits, as when we see him to be haughty or to become inordinately angry or [to display] other unsightly traits, which [i.e., the possession of which traits] is absolutely degrading. And though it be true [that he did act as related of him], who knows if he did not repent in bitterness of heart over these evil traits? And even if one saw that he was habituated to these evil traits and that he was not bitter over them at all — in spite of this, it is forbidden to berate him. For perhaps he is unaware of the gravity of the issur. For, in truth, we see it patently in many individuals, even (sometimes) in Torah scholars, that they do not regard these evil traits as such a grave issur — as they are, indeed, in truth, to those who contemplate them in Scripture and in the words of Chazal — but only as something not quite appropriate. And perhaps this sinner, too, is of this mind. And if he knew the true gravity of the issur, it is possible that he would exert all of his powers not to transgress them (viz. Shabbath 69a): "If he [the sinner] were "unwitting" [shogeg] relative to kareth ["cutting- off"], (i.e., if he did not know that the sin were punishable by the grave penalty of kareth, and he were "witting" relative to [having transgressed] a negative commandment, his act is called "unwitting" [in that he is not aware of its full gravity]). To the contrary, if one sees that he [the sinner] is habituated to one of these evil traits, he should reprove him and impress upon him the gravity of the issur. And in this he would be fulfilling the positive commandment of "Reprove shall you reprove your fellow." And it is possible that he would admit that he was doing wrong, but that at the time his way was just in his eyes, viz. (Mishlei 21:2): "A man's every way is just in his eyes." Therefore, it is forbidden to perceive him as "wicked" and to go and speak [demeaningly] of him.