-Part One, The Prohibition Against Lashon Hara, Principle 2, Seif 11
And now, according to what we have explained, with the help of the Blessed L–rd, of the principles of apei telata, [we realize that] care must be taken that when the seven city dignitaries preside over the actions of the men of the city in matters of assessments and the like, where their judgment will be to the detriment of one and to the benefit of another, and they differ in opinion and decide according to the majority — when they leave the communal chamber, each one must take great heed not to relate thereafter his opinion or the opinion of Ploni to the effect that in the beginning of the case his opinion was to be lenient with the man involved, but his colleagues overruled him and compelled him to accept their view. And it goes without saying that if they agreed among themselves from the beginning that when they left the communal chamber they would not reveal or relate their deliberations to the man involved in the debt — [it goes without saying] that if he did so, this would be an absolute issur; but even if quite casually, without even intending to reveal anything, he happened to tell this to another in such a manner as to make it appear from his words that he did not incline to this [the majority opinion] even now, but that he could not contest it with the others, this, too, is an absolute issur. (And according to the opinion of Hayad Haketanah (Hilchoth Deoth 9) even if one relates casually that it was his opinion in the beginning to be lenient with the man involved, but it came to a vote and they decided according to the majority, this, too, is forbidden.) And there is no difference between whether one reveals this of his own volition or his friend rises against him with insults over this decision which they arrived at in a certain matter. In all instances it is forbidden to place the onus on his colleague and remove it from himself, even if what he says is true.
-Part One, The Prohibition Against Lashon Hara, Principle 2, Seif 12
I have also found it fitting to write of another thing explicitly, for I have found many people to be habituated to it. That is, when someone lectures in the house of study it is forbidden according to the din to mock him and to say that there is nothing to his lectures and there is nothing to hear. And in our many sins we see many people to be remiss in this, not considering this mockery as an issur at all. But according to the din it is absolute lashon hara. For through such speech it often happens that he causes monetary loss to his friend, and, sometimes, pain and shame, too. For even if it were true, lashon hara is forbidden even if true. For what benefit does this mocker and jester hope to gain by his levity? If he is a sincere person, to the contrary, he should counsel him [the lecturer] afterwards, in private, and suggest other ways to present his lecture. For in his present approach [mockery], his words are not attended to; and by this [the above] counsel [to the lecturer] he would also fulfill (Vayikra 19:18): “And you shall love your neighbor as yourself.” In any event, he should not render him a mockery in the mouths of men. And the heter of apei telata is of no avail here as I have clearly explained in the Be’er Mayim Chayim.
-Part One, The Prohibition Against Lashon Hara, Principle 2, Seif 13
If one revealed to his friend, in the presence of three, details of his occupation or trade or the like, things which, in general, are otherwise forbidden to repeat afterwards to another, lest this result in injury or pain to him — now, since he himself revealed it in the presence of three, it is evident that this is of no concern to him, even if it comes to be known in the end. Therefore, the one who hears it from him is permitted ab initio to reveal it to others, so long as he [the teller] does not make it clear that he is opposed to his doing so. [But none of the qualifications adduced above in the discussion of apei telata should be lacking. See Be’er Mayim Chayim.]