זֹאת תִּהְיֶה תּוֹרַת הַמְּצֹרָע – This will be the law of the metzorah [leper]. (Leviticus 14:2)
The gemara teaches that metzorah means motzi shem rav – to cause someone to have a bad reputation; that is, to speak Lashon Harah. It is told that one evening the great Chafetz Chaim was walking in his town of Rahdin during a heavy rain. The streets were empty but for a lone Jewish stranger whose carriage passed him and asked, ‘where lives the town’s rabbi, the tzaddik, the Chafetz Chaim?’ The scholar said of himself, ‘firstly he is no rav and secondly he is no tzaddik.’ Said the stranger in astonishment, ‘But everyone holds him to be a man of great faith and righteousness!’ The rabbi’s reply, ‘I know the Chafetz Chaim very well and I assure you that is a great exaggeration and tall tale.’ The stranger became enraged; he cursed the scholar and then hit him with the whip in his hands. The rabbi was greatly troubled that he had caused the stranger to transgress in such a way. A while later when the Chafetz Chaim returned home he found the stranger waiting at his door. When the stranger realized what he had done, he was so shaken he nearly fainted. The rabbi said to him, ‘you did nothing wrong as I deserved the beating; for not only is it forbidden to speak Lashon Harah about others, it is also forbidden to speak Lashon Harah about oneself.’