This week’s Torah reding of M’tsora (Leviticus 14:1–15:33) deals at length with regulations pertaining to a person diagnosed with a dermatological ailment usually translated as leprosy. To the talmudic sages, this disease was a divine punishment for the sin of wicked speech—more precisely, any sort of disparagement of a fellow person. Reflecting on why rabbinic thought ascribes such gravity to this particular sin, Jonathan Sacks seeks the answer in the Jewish view of speech itself:

There are ancient cultures who worshipped the gods because they saw them as powers: lightning, thunder, the rain and sun, the sea and ocean that epitomized the forces of chaos, and sometimes wild animals that represented danger and fear. Judaism was not a religion that worshipped power, despite the fact that God is more powerful than any pagan deity. Judaism, like other religions, has holy places, holy people, sacred times, and consecrated rituals. What made Judaism different, however, is that it is supremely a religion of holy words. With words God created the universe: “And God said, Let there be . . . and there was.” Through words He communicated with humankind. In Judaism, language itself is holy. . . .

Words are remarkable in another way as well. We can use language not just to describe or assert. We can use it to create new moral facts. The Oxford philosopher J.L. Austin called this special use of language “performative utterance.” The classic example is making a promise. When I make a promise, I create an obligation that did not exist before. . . . Hence the idea at the heart of Judaism: covenant, which is nothing other than a mutually binding promise between God and human beings.

It follows that to misuse or abuse language to sow suspicion and dissension is not just destructive. It is sacrilege. It takes something holy, the human ability to communicate and thus join soul to soul, and uses it for the lowest of purposes, to divide soul from soul and destroy the trust on which non-coercive relationships depend. That, according to the sages, is why the speaker of wicked words was smitten by leprosy and forced to live as a pariah outside the camp.