Now picture the same word or phrase written in large letters across your forehead for all the world to see - in fact, this word or phrase, this blemish across your forehead, is the first thing people notice about you.
How would other people react to your blemish? Would it change how they treat you? What do you think you would need to do to clear your skin?
(א) וַיְדַבֵּ֥ר יי אֶל־מֹשֶׁ֥ה לֵּאמֹֽר׃ (ב) זֹ֤את תִּֽהְיֶה֙ תּוֹרַ֣ת הַמְּצֹרָ֔ע בְּי֖וֹם טָהֳרָת֑וֹ וְהוּבָ֖א אֶל־הַכֹּהֵֽן׃
(1) Adonai spoke to Moses, saying: (2) This shall be the ritual for a metzora ("leper") at the time that he is to be cleansed. When it has been reported to the priest...
...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 --metzora--and turned it into a pun. They said that the metzora is the person who is motzi ra, someone who says bad things about other people.
The Hebrew term for leprosy [has] various meanings...The whiteness in a man's skin is called leprosy; the falling off of some hair on the head or the chin is named leprosy; and a change of color in clothing or in houses is referred to as leprosy. Now this change in clothes and in houses which the Torah has called leprosy... is not a natural phenomenon, but was deemed a sign and a wonder among the people of Israel to warn them against evil gossip. If a man dealt out malicious gossip, the walls of his house would change; if he repented, the house would become clean again. But if he persisted in his wickedness until the house was demolished, leather objects in his home upon which he would sit or lie would then suffer a change; if he repented, they would become clean again. But if he persisted in his wickedness until they had to be burned, the clothes which he wore would undergo a change; if he repented, they would become clean again. But if he persisted in his wickedness until they had to be burned, his skin would suffer a change and he would become leprous, and be set apart and exposed all alone, so as not to engage in evil talk, which consists of mockery and malicious gossip.
(כא) מָ֣וֶת וְ֭חַיִּים בְּיַד־לָשׁ֑וֹן...
(21) Death and life are in the the hand [power] of the tongue...
It was said before Rav Naḥman bar Yitzḥak: Anyone who humiliates another in public, it is as though he were spilling blood. Rav Naḥman bar Yitzḥak said: You have spoken well, as we see that after the humiliated person blushes, the red leaves his face and pallor comes in its place, which is tantamount to spilling his blood.
Know that a word suddenly shot from the tongue is like an arrow shot from the bow. Son, that arrow won't turn back on its way; you must dam the torrent at its source.
This is not a natural, earthly phenomenon, just as in the case of house leprosy; rather, when Israel is one with God, God's spirit is always upon them to keep their bodies and their garments and houses appearing well. But when one of them sins or transgresses, an ugliness appears in his body or his garment or his house to show that God has left him. (Nachmanides)
The tzara'at lesions which Scripture lists as rendering the victim unclean have nothing in common with the leprous diseases known to medicine. Tzara'at is a supernaturally caused affliction imposed by God on man to punish him for a sin or to atone for a wicked deed. (Sforno)
In biblical Israel, the kohen was both the religious and the medical authority. The biblical mind saw the connection between the physical and the spiritual dimensions of illness and recovery (perhaps more clearly than we see it today). (Chumash Etz Hayim)