נוצות ברוח

Keep thy tongue from evil, And thy lips from speaking guile.

Who is a sycophant? One who loads himself up with matters, and goes from this one to that one, saying to each, such did that man say, thus and such have I heard concerning that man, even though it be true, behold him, he destroys the universe. There is yet an extremely grosser iniquity, which, too, is included in this prohibitive commandment, and that is, the evil tongue, one who spreads scandal about his fellow even though he be telling truth. If he be lying, he is called a maligner who invents an evil name against his fellow. The owner of an evil tongue, behold him, he sits in company and relates, saying: thus and such did that certain party, thus and such were his parents, and thus and such I did hear about him and of course, he relates scandalous matters. Of him, the Verse says: "May the Lord cut off all flattering lips, the tongue that speaketh proud things" (Ps. 12.4).

Another interpretation: "This shall be the law for a leper" - this is what is written (Psalms 36:13), "Who is the man who desires life?" There is a story of a peddler who would go around to towns that were close to Tzippori. He would shout out and say, "Who wants to buy the [potion] of life?" They would [all] cling to him. Rabbi Yannai was sitting and interpreting [texts] in his reception room [and] heard him shouting out, "Who wants to buy the [potion] of life?" [Rabbi Yannai] said, "Come down to here, sell [it] to me." He said [back] to him, "You do not need it and those like you do not [need it]." [Nonetheless,] he made the effort to come and go down to him. He took out a book of Psalms and showed him the verse, "Who is the man who desires life?" [The peddler said,] "What is written after it - 'guard your tongue from evil [...] Turn away from evil and do good' (Psalms 34:14-15)." Rabbi Yannai said, "Shlomo also shouted out and said (Proverbs 21:23), 'He who guards his mouth and his tongue, guards his soul from troubles.'" Rabbi Yannai said "All of my days I was reading this verse and I did not know how to interpret it until this peddler came and made it understood - 'Who is the man who desires life?'" Therefore, Moshe warns Israel and says to them, "This shall be the law for a leper (metsora)" - the law of the one that gives out a bad name (motsee shem) [to another].