Musar su Proverbi 26:18

And there is another wrong which smacks of gossip — for example, where a person says, "Oh, better be silent about so and so; I don't want to say what I know about him!" — and so in all similar cases. And our Sages further said, "Let no man ever talk in praise of his neighbor, for through his praise he will come to disparage him" (Arakin 16a, and see Baba Bathra 164b). The meaning of this is: if you praise a man to his enemy, he will retort, "How can you praise him so much when he does this and this." And concerning this it is said, "He that blesseth his friend with a loud voice, rising early in the morning, it shall be counted a curse to him" (Prov. 27:14). But to praise a man before his friends is permitted, as we have learned, "Rabban Johanan the son of Zakkai had five (outstanding) disciples, and he used to recount their praises" (Aboth 2:8). Then, there is the one who speaks gossip by way of a joke or by way of frivolity (that is, he is not speaking out of hatred), and that is what Solomon said in his wisdom, "As a madman who casteth firebrands, arrows and death; so is the man that deceiveth his neighbour and saith: "Am not I in sport?" (Prov. 26:18—19).