Musar su Osea 4:4

And contemplate this well to understand the principle of this matter: Behold we mentioned earlier that it is permissible to speak in disgrace of the sinner about the theft that is in his hands, if it is known that he has not left his path. For example, the robber and the extortionist, the damager and the harasser, the one who whitens the face [of another], the one who makes [others] fowl and shameful and the one who speaks evil speech - [if] he has not returned the theft, or payed for his damage or requested from his fellow to remove his iniquity (to forgive him). However those that see their ways must surely first speak to the sinner - perhaps they will be able to help by way of a reprimand to have him repent from his evil way. And if he surely refuses, they may then inform the public about his ways and deeds.
However a person can be blamed from the deed of his fellow that was wanton against his fellow, when he recounts his deeds to people and reveals the obligations of the sinner and disgraces his acts with various claims: Behold, the recounter will be suspected about this and they will think him one engaged in evil speech. And they will surely say, “Even if the thing was true, it would have been fitting to reveal it to the ear of the sinner as a reprimand first.” And his listeners will suspect him about his not giving him a reprimand first, saying that he would not have said all of this in front of [the sinner] and he is flattering him - like the matter that is stated (Hosea 4:4), “Let no man rebuke, let no man protest!” And [they will further say that] he enjoys speaking about the guilt of the people, the iniquity of which brings him joy and the disgrace of which brings him honor when it is not front of them; and he is similar to someone involved in evil speech and is clinging to its dust. And people will also say, “The things are not true and he made them up from his heart. And, however if not, why did he not reveal his iniquity in front of him first, but rather ignore him?” Hence our Rabbis said (Arakhin 15b), “Any statement that is said in the presence of its master (i.e., the subject of the statement) is not in the way of evil speech. It means to say that if he previously gave an open reprimand to his fellow about his deed, and [the latter] did not pay attention to his words - he may afterwards inform people of that man’s guilt and the evil of his conduct. And he will not be suspected of wanting to give his fellow a defect. And likewise if the teller is assumed by the public not to seek the favor of any man and not to bend to a man; and everything he would say not in front of his fellow, he would [also] say in front of him and not be frightened by any man; and he also be assumed among his people to only speak the truth - he is not to be suspected when he speaks about the guilt of his fellow not in front of him. And so did they mention in their words, may their memory be blessed, about this matter and say, “Rabbi Yose says, ‘From [all of] my days, I have never said a word and turned around behind me.’” He meant to say, “I have never said something about a person not in front of him, but suppressed it when I was in front of him.” They also said, “Anything that is said in front of three is not in the way of evil speech.” It means to say - since there were many [people] with him at the time that he told the thing, hence the thing will be known to his fellow. And behold it is as if he said the words in front of him.