Halakhah for Arakhin 31:6

The details of the commandment and the great amount of warnings that they, may their memory be blessed, warned us about talebearing and about its partner - evil speech - are explained in scattered locations in the Talmud and in the Midrash (see Mishneh Torah, Laws of Human Dispositions 7). And they explicitly said about evil speech (Arakhin 15b), that it kills its speaker and its receiver (listener), (and) that it is said about it, "and the receiver more than all of them [does it kill]." And they warned much about it to the point that they said (Bava Metzia 59b), "One who has someone who was hung in his [family] record, let him not say, 'Hang me a fish [on the grill].'" And they said, (Arakhin 16a), "Within the category of 'the dust of (adjunct)' evil speech is one who praises his friend in front of [his friend's] hater, as it is stated (Proverbs 27:14), 'He who blesses his friend, etc.'"