“…A person to whom shall occur in the skin of his flesh a se’eis, or sapachas, or baheres [patches of varying degrees of whiteness], and it be in the skin of his flesh the plague of tzora’as…” – Vayikra 13:2

אָדָם כִּי יִהְיֶה בְעוֹר בְּשָׂרוֹ שְׂאֵת אוֹ סַפַּחַת אוֹ בַהֶרֶת וְהָיָה בְעוֹר בְּשָׂרוֹ לְנֶגַע צָרָעַת – ויקרא יג, ב

The occurrence of tzora’as, says the Talmud (Arachin 16a), is G-d’s supernatural means of deterring a person from lashon hara, speaking derogatorily about another person.

We find, however, that the Rambam, after mentioning the link between tzora’as and lashon hara, goes on to elaborate about other forms of undesirable speech. In his words: “This is the pattern of the gatherings of the wicked scoffers: In the beginning, they speak excessively about empty matters… Because of this, they come to speak negatively of the righteous… Consequently, they will become accustomed to speaking against the prophets and casting aspersions on their words… Ultimately, this leads them to deny G-d’s existence entirely… This is the speech of the wicked…” (Hilchos Tum’as Tzora’as 16:10).

In doing so, the Rambam identifies and defines the essential pitfall of speaking lashon hara, even in instances where it brings no harm to the person spoken about, nor does it stem from the evil character of the one speaking. [In fact, the classic example of someone afflicted with tzora’as for speaking lashon hara is Miriam, (see Devarim 24:8-9, “Take care with regard to the condition of tzora’as… Remember what Hashem your G-d did to Miriam,”) who was exceptionally righteous and intended no harm to Moshe when she spoke about him.] Rather, the detriment of lashon hara is in the undesirable speech itself. For the faculty of speech, despite being merely a tool of outward expression, is rooted deep within the soul; indeed the Jewish philosophers categorize the human being as “the one who speaks.” Consequently, even when lashon hara seems meaningless, it has the potential to draw even an otherwise righteous person much deeper into evil. To paraphrase the Rambam, the “speech of the wicked” at any level—lashon hara included—can ultimately lead a person even to heresy.

This then is the purpose of tzora’as: to warn those affected to change their speaking habits immediately, to prevent their seemingly harmless lashon hara from having profound negative effects on their character.

—Likutei Sichos, vol. 22, pp. 66-68