Halakhah sa Deuteronomio 24:9: Chafetz Chaim & Mishneh Torah, Defilement by Leprosy

And now I shall begin, with the help of the Blessed L–rd to explain how many positive commandments one transgresses in speaking lashon hara and rechiluth, as we projected above.
One who bears tales against his friend, aside from transgressing the negative commandments we mentioned above, also transgresses several positive commandments, which I shall explain, with the help of the Blessed One, one by one.
(1) He transgresses thereby (Devarim 24:9): "Remember what the L–rd your G–d did to Miriam on the way when you went out of Egypt." The Torah exhorted us hereby that we mention verbally, always, the great punishment [leprosy] that the Blessed L–rd brought upon the tzadeketh, Miriam the prophetess — who spoke only about her brother, whom she loved as her soul, whom she raised on her knees, and for whom she endangered her life, to rescue him from the Nile. And she did not speak in denigration of him, but only compared him to other prophets. And she did not speak so to his face to shame him, and not in public, but only to her brother Aaron, privately. And he [Moses] was not offended by all this, viz. (Bamidbar 12:3): "And the man Moses was extremely humble, more than any man on the face of the earth" — in spite of which all her good deeds did not avail her and she was punished with leprosy for this. How much more so will other people, the fools, who are prolix in speaking "great and awesome things" against their friends, be severely punished for this.

Tsaraat is a name given collectively to many different matters that are not similar to each other. As, behold, the whitening of a person's skin is called tsaraat and the falling out of a little bit of head or beard hair is [also] called tsaraat and [even] the change of the hue of clothing or houses is called tsaraat. This change mentioned with clothing and houses that the Torah collectively called tsaraat is not [like] the way of the world, but rather it is a sign and a wonder that [existed] in Israel to caution them about evil speech (lashon hara), such that the walls of the one that spoke evil speech would change [color]. If he repented, the house would become pure. [But] if he persisted in his evil until his house was broken down, the leather vessels that he would sit and recline upon would change [color]. If he repented, they would become pure. [But] if he persisted in his evil until they were burned, his skin would change [color] and he would become infested with tsaraat, and he would be isolated and [his condition would be] publicized until he would not be involved in the speech of the evildoers, which is mockery and evil speech. And about this matter the Torah cautions and says beware of the plague of tsaraat: "Remember that which the Lord, your God, did to Miriam on the way" (Deuteronomy 24:9). Behold, it is saying, "Reflect upon what happened to Miriam the prophetess, who spoke about her brother." She was older than him and raised him on her knees and endangered herself to save him at the sea, and she did not speak in his derision but rather erred in comparing him to other prophets - and he was not [even] exacting about all of these things, as it is stated (Numbers 12:3), "And the man, Moshe, was very humble." And nonetheless, she was immediately punished with tsaraat. All the more so is it with silly evil people who frequently speak boastfully and about [supposed] wonders. Therefore, it is fitting for the one who wants to guide his ways to distance himself from their gatherings and from speaking with them, so as not to be snagged by the net of evildoers and their foolishness. And this is the way of the gatherings of scoffers: At first, they speak much about useless things, as the matter is stated (Ecclesiastes 5:2), "and the voice of a knave is with many words." And from this, they come to speak derisively about the righteous, as the matter is stated (Psalms 31:19), "Silence the lips of falsehood, that speak harshly about the righteous." And from this, they will be accustomed to speaking about prophets [derisively] and to cast a doubt upon their words, as the matter is stated (II Chronicles 36:16), "They would insult the messengers of God, and disgrace His words and confound His prophets." And from this, they come to speak [derisively] about God and denying a principle of faith, as the matter is stated (II Kings 17:9), "And the Children of Israel covered up things about the Lord, their God, that were not so." And behold, it states, (Psalms 73:9), "They have set their mouths against the heavens and their tongues walk upon the earth:" Who caused them to set against the heavens their mouths? Their tongue that first walked upon the earth - which is the conversation of the evildoers, which causes them to sit at corners and sit at the gatherings of ignoramuses and sit at parties with drinkers. But the conversation of the proper ones of Israel is only in the words of Torah and wisdom. Therefore, the Holy One, blessed be He, helps their hand and grants them merit in it, as it is stated (Malachi 3:16), "Then those that fear the Lord spoke, one man to his fellow; and the Lord listened and heard, and a book of remembrance was written in front of Him for those that feared the Lord and those that gave importance to His name." The Laws of Defilement by Leprosy have been completed.