זֹאת תִּהְיֶה תּוֹרַת הַמְּצֹרָע בְּיוֹם טָהֳרָתוֹ וְהוּבָא אֶל הַכֹּהֵן (ויקרא יד, ב): This shall be the law of the metzorah...
The Midrash (ויק"ר ט"ז ב') cites this Passuk and expounds on it as follows.
זאת תהיה תורת המצורע הה"ד מי האיש החפץ חיים - This shall be the law of the metzorah, thus it is written, ‘Who is the man who desires life and loves days that he may see good? Guard your tongue from evil and your lips from speaking deceit’. The Medrash continues and relates an incident which teaches us the significance of this message.
An incident took place with a peddler who would make his rounds in the towns which were in the vicinity of Tzipori, and announce; “Who wishes to acquire a life-giving drug?” Whenever he would make this announcement, people would cling to him, anxious to hear more about this drug. One time when R’ Yannai was sitting and studying in his reception room, he heard this peddler making his announcement. R’ Yannai promptly called the peddler over and asked to purchase this drug. The peddler replied, “Neither you nor any like you have any need for that drug which I have to sell”. Nevertheless, because R’ Yannai persisted, the peddler came close to him, and showed him the Passuk in Tehillim, מי האיש החפץ חיים אוהב ימים לראות טוב – ‘Who is the man who desires life and loves days that he may see good?’ The peddler then showed R’ Yannai what is written thereafter, נצור לשונך מרע - ‘Guard your tongue from evil’. This Passuk indicates that guarding one’s tongue from speaking ill of others is the key to preserving one’s life and to seeing good days. R’ Yannai then said; Shlomo Hamelech proclaimed similarly in Mishlei (כ"א כ"ג) and said, שומר פיו ולשונו שומר מצרות נפשו - ‘One who guards his mouth and tongue, guards his soul from troubles’. Subsequently, R’ Yannai said; All my life I have read this Passuk, yet I never knew how it is to be understood, until this peddler came and made known to me the importance of ‘Who is the man who desires life’.
We need to understand what it was about this Passuk in Mishlei that at first R’ Yannai didn’t understand, and why only after hearing the words of the peddler, who seemingly did nothing other than show R’ Yannai a Passuk in Tehillim, did the meaning of the Passuk in Mishlei become clear to him?
The Midrash Tanchuma brings the Passuk in Mishlei, שומר פיו ולשונו נפשו מצרות שומר - One who guards his mouth and tongue, guards his soul from troubles, and modifies it, as if it were to say, שומר פיו ולשונו נפשו מצרעת שומר - One who guards his mouth and his tongue guards his soul from tzaraas.
What R’ Yannai did not understand about this Passuk before the peddler came along, was why the Passuk would say, נפשו שומר מצרעת – he guards his soul from tzaraas, when it should have said, גופו שומר מצרעת - he guards his body from tzaraas, for tzaraas inflicts the person’s body and not the person’s soul?
When the peddler announced, “Who wishes to acquire a life-giving drug?” and then went on to show R’ Yannai the Passuk, מי האיש החפץ חיים, אוהב ימים לראות טוב, נצור לשונך מרע - ‘Who is the man who desires life and loves days that he may see good? Guard your tongue from evil’, this caused R’ Yannai to reflect and realize that the tzaraas that inflicts the slanderer isn’t a tzaraas that merely inflicts the slanderer’s body, rather it endangers the slanderer’s life, too. Accordingly, the Passuk would be understood as follows; ‘One who desires life’ [and doesn’t want to endanger it with the tzaraas that can endanger the slanderer’s life], and also ‘loves days that he may see good’ [and doesn’t want to ruin his days with the tzaraas that inflicts the slanderer’s body], should ‘guard his tongue from evil’.
As a result of this new understanding of the Passuk in Tehillim, R’ Yannai also gained an understanding of the Passuk in Mishlei. The Passuk says, שומר פיו ולשונו שומר מצרות נפשו - One who guards his mouth and his tongue guards his soul from troubles, and while the Tanchuma does modify the Passuk to read, נפשו מצרעת שומר - guards his soul from tzaraas, nevertheless it still wouldn’t read מצרעת שומר גופו - guards his body from tzaraas, for although, in truth, the tzaraas is only found on the slanderers body and not on his soul, nevertheless the tzaraas doesn’t merely inflict his body, rather it also inflicts him in a way which is a danger to his life, and thus, the tzaraas is indeed an infliction to the slanderers soul, as well.
(זרע שמשון פרשת מצורע אות ז)
