(מג) וְרָאָ֨ה אֹת֜וֹ הַכֹּהֵ֗ן וְהִנֵּ֤ה שְׂאֵת־הַנֶּ֙גַע֙ לְבָנָ֣ה אֲדַמְדֶּ֔מֶת בְּקָרַחְתּ֖וֹ א֣וֹ בְגַבַּחְתּ֑וֹ כְּמַרְאֵ֥ה צָרַ֖עַת ע֥וֹר בָּשָֽׂר׃ (מד) אִישׁ־צָר֥וּעַ ה֖וּא טָמֵ֣א ה֑וּא טַמֵּ֧א יְטַמְּאֶ֛נּוּ הַכֹּהֵ֖ן בְּרֹאשׁ֥וֹ נִגְעֽוֹ׃ (מה) וְהַצָּר֜וּעַ אֲשֶׁר־בּ֣וֹ הַנֶּ֗גַע בְּגָדָ֞יו יִהְי֤וּ פְרֻמִים֙ וְרֹאשׁוֹ֙ יִהְיֶ֣ה פָר֔וּעַ וְעַל־שָׂפָ֖ם יַעְטֶ֑ה וְטָמֵ֥א ׀ טָמֵ֖א יִקְרָֽא׃ (מו) כָּל־יְמֵ֞י אֲשֶׁ֨ר הַנֶּ֥גַע בּ֛וֹ יִטְמָ֖א טָמֵ֣א ה֑וּא בָּדָ֣ד יֵשֵׁ֔ב מִח֥וּץ לַֽמַּחֲנֶ֖ה מוֹשָׁבֽוֹ׃ (ס)
(43) The priest shall examine him: if the swollen affection on the bald part in the front or at the back of his head is white streaked with red, like the leprosy of body skin in appearance, (44) the man is leprous; he is unclean. The priest shall pronounce him unclean; he has the affection on his head. (45) As for the person with a leprous affection, his clothes shall be rent, his head shall be left bare, and he shall cover over his upper lip; and he shall call out, “Unclean! Unclean!” (46) He shall be unclean as long as the disease is on him. Being unclean, he shall dwell apart; his dwelling shall be outside the camp.
(מה) וטמא טמא יקרא. מַשְׁמִיעַ שֶׁהוּא טָמֵא וְיִפְרְשׁוּ מִמֶּנּוּ (ספרא, מועד קטן ה'):
AND HE SHALL CALL OUT, UNCLEAN, UNCLEAN — he must proclaim aloud that he is unclean, so that people may keep away from him (Sifra, Tazria Parashat Nega'im, Chapter 13 7; Moed Katan 5a).
Why must the unclean person announce his affliction?
(מו) בדד ישב. שֶׁלֹּא יִהְיוּ טְמֵאִים יוֹשְׁבִין עִמּוֹ; וְאָמְרוּ רַבּוֹתֵינוּ מַה נִּשְׁתַּנָּה מִשְּׁאָר טְמֵאִים לֵישֵׁב בָּדָד? הוֹאִיל וְהוּא הִבְדִּיל בִּלְשׁוֹן הָרָע בֵּין אִישׁ לְאִשְׁתּוֹ וּבֵין אִישׁ לְרֵעֵהוּ, אַף הוּא יִבָּדֵל (ערכין ט"ז):
HE SHALL ABIDE SOLITARY — ...Our Rabbis said: Why is he (the leper) treated differently from other unclean persons that he should abide solitary? They replied: Because he, by slanderous statements (lashon hara), (cf. Numbers 12:10) parted man and wife, or a man from his friend, he must be parted from everybody (Arakhin 16b).
"...Back in ancient times when people got sick, they often thought that it was because of something they had done; they thought that it was direct punishment for moral sins. Knowing that, it's not surprising to learn the ancient sages' response to why people got afflicted with tzara'at. They took the word for the one who is afflicted --metsora'--and turned it into a pun. They said that the metsora' is the person who is motzi ra, someone who says bad things about other people." (Jeffrey Salkin, JPS B'nai Mitzvah Torah Commentary, 131.)
“Whoever shames his neighbor in public, it is as if he shed his blood.” (Bava Mezia 58b)
“Life and death are in the hands of the tongue.” (Pro. 18:21)
“It is forbidden to call someone by a name they dislike.” (Maimonides, Law of Character Development 6:8)
“One who gives his neighbor a bad name, can never gain pardon.” (Bava Kamma 8:7)
“Even if we upset somebody only through harsh words, without committing any tangible act of injury, we are still required to seek forgiveness.” (Maimonides, Laws of Repentance, 2:9)
“If the humiliation took place in the presence of others, make your apology in their presence, as well as in private. Otherwise the victim has the right to say, ‘You shamed me in front of others, and now you want to apologize in private. Bring me all the people who heard you embarrass me, and then I will accept your apology.’” (Yalkout Shimoni, Hosea 14)