Musar do Liczb 12:10

And they also expounded (in Vayikra Rabbah 16) the verse (Koheleth 5:5): "Do not allow your mouth to cause sin to your flesh" — do not speak lashon hara with your mouth to punish all of your flesh with this sin. The Rabbis applied this verse to Miriam: "Do not allow your mouth" — you, Miriam, as it is written (Numbers 12:10): "And, behold, Miriam was leprous, [white] as snow." (Koheleth, Ibid.): "that it was an error" — as it is written (Numbers 12:11): "wherein we [(Aaron and Miriam)] have erred and wherein we have sinned." (Koheleth, Ibid.): "Why should G-d be angry at your voice?" — at the lashon hara you have spoken against Moses, as it is written (Numbers 12:9): "and the anger of the L-rd burned against them, and He departed." (Koheleth, Ibid.): "and [He shall] destroy the work of your hands." R. Yochanan said: "With her mouth she sinned, and all her limbs were smitten, as it is written (Numbers 12:10): 'And the cloud departed from the tent, and, behold, Miriam was leprous, [white] as snow.' This is the intent of: "Do not allow your mouth to cause sin to [destroy] your flesh" … (Mishlei 21:33): 'He who guards his mouth and his tongue guards his soul from troubles.'"

והנה מרים מצורעת כשלג . Here we see the severity of the sin of gossiping. Look at what happened to the prophetess Miriam who had indulged in an ordinary conversation with her brother Aaron, making some remark about her brother Moses! We are reminded to recite the verse זכור את אשר עשה ה' אלוקיך למרים בדרך בצאתכם ממצרים, "Remember what the Lord your G–d has done to Miriam on the way when you had come out of Egypt" (Deut. 24,8). It is one of the six זכירות, commemorations, a person is to recite daily.

The person suffering from צרעת, however, is afflicted with the essence of the impurity, and there is no way for him to avoid it. Hence he has to leave all three camps as long as he is afflicted. Such impurity in any Jew is of the kind that infects even the נפש, i.e. part of the camp of the Israelites. This is in accordance with Proverbs 21,23 שומר פיו ולשונו שומר מצרת נפשו – that "he who guards his mouth and tongue, keeps his soul from troubles." The Zohar suggests that the reading of מצרת is equivalent to מצרעת, i.e. from that skin eczema. Our sages are agreed that evil gossip is a principal cause of this affliction. Classic examples are Miriam (Numbers 12,10), and Moses (Exodus 4,6), both of whom were punished for having made inappropriate comments about Moses or Israel respectively. We observe many slanderers in our day who are never afflicted with this disease; this makes the matter even worse for them, since they have already forfeited the part of the נפש that would be stricken, and they are therefore no longer capable of being rehabilitated through that disease and the subsequent purification process. The מצורע, at any rate, has to leave all three camps.