According to the Sages, the leprosy discussed in the Torah was often the punishment for malicious speech. The Sages likened speaking slander to shooting an arrow, which can easily kill even someone far away.

Our Sages said: Leprosy afflicts a person only due to the slander that emerges from his mouth. The verse states: “This shall be the law of the leper” (Leviticus 14:2) – this is consistent with what the verse says: “Death and life are in the power of the tongue” (Proverbs 18:21). Everything is contingent on the tongue: If a person merits – he will merit life, if he does not merit – he will be condemned to death. If a person engaged in Torah with his tongue – he merits life, as the Torah is called life…and Torah study is his cure for slander. If he engaged in slander – he has condemned his soul to die, as slander is more severe than bloodshed. As one who kills, kills only one soul, while one who speaks slander kills three: the one who speaks the slander, the one who accepts it as true, and the one about whom it was spoken. Who is more dangerous: One who strikes another with a sword or one who strikes him with an arrow? You must say that one who strikes another with an arrow is more dangerous. One who strikes another with a sword can kill another only if the attacker drew near to him and touched him, which is not the case with one who strikes another with an arrow. He shoots the arrow and strikes him anywhere that he sees him. That is why the speaker of slander is likened to one who attacks with an arrow, as it is stated: “A sharpened arrow is their tongue…” (Jeremiah 9:7). Alternatively: “Death and life are in the power of the tongue” means as follows: Do not say: Since I have been given license to speak, I will speak anything that I please. The Torah has already cautioned you: “Guard your tongue from evil and your lips from speaking deceit” (Psalms 34:14). Lest you say that as a result of refraining from such speech you will lose, you will only gain. The divine inspiration shouts: “He who guards his mouth and his tongue guards himself from troubles [(Tanĥuma [Buber], Metzora)