If a person will have on the skin of his flesh a s’eis, sapachas, or baheres, and it will become a tzaraas affliction on the skin of his flesh; he shall be brought to Aharon the Kohen, or to one of his sons the Kohanim.
We need to understand why the laws regarding the tzaraas were given over to the Kohanim for them to rule upon, whereas the laws regarding all other areas of the Torah were given over to the Torah Scholars to decide upon. Furthermore, the Midrash tells us צער גדול היה לו למשה בדבר הזה,(ויק"ר ט"ו ח') כך הוא כבודו של אהרן אחי להיות רואה את הנגעים, אמר לו הקב"ה, ולא נהנה ממנו כ"ד מתנות כהונה - Moshe was greatly troubled over Aharon’s involvement with examining skin afflictions. He wondered, “Is this befitting the honor of my brother Aharon, to examine people’s tzaraas afflictions?” Hashem replied, “And does he not receive the twenty-four priestly entitlements?” Hashem’s reply to Moshe definitely needs explanation, as what do the twenty-four priestly entitlements have to do with Aharon checking the tzaraas?
The Midrash
(ויק"ר ט"ז א') comes to explain unto which sin the tzaraas comes as a punishment, and says as follows. When Moshe cautioned the Jews; (י"ד ב')זאת תהיה תורת המצורע - This shall be the law of the metzorah, the word 'מצורע' may be expounded as a contraction of מוציא שם רע, thus it is as if the Torah wrote; זאת תהיה תורת המוציא שם רע - This shall be the law of the defamer.
The Sages thus explain, that the Torah uses the word מצורע in this Passuk, as opposed to the more commonly used word of צרוע, to teach us that that it is one who is מוציא שם רע who will be punished with tzaraas.
In regards to someone who is מוציא שם רע, the Gemara in Kidushin (ע ע"א) teaches us that כל הפוסל פסול וכו' ואמר שמואל במומו פוסל – Whoever declares others to be genealogically unfit is himself genealogically unfit. That is, anyone who regularly demeans the genealogical status of other families, reveals himself to be genealogically blemished. The Gemara continues on (עא ע"ב) and says, דבדקי בני מערבא, כי מינצו בי תרי בהדי הדדי חזו האי מינייהו דקדים ושתיק אמרי האי מיוחס טפי. אמר רב שתיקותיה דבבל היינו יחוסא - The following method was used by the people of Eretz Yisroel when they would investigate someone’s lineage; When two people would quarrel with each other, they would see which one is the first to quiet down and they would say, “That person is genealogically purer than the other”. Rav said, “The silence and peacefulness of the families in Bavel is the basis for their having been established as possessing genealogical fitness”.
The Rambam
(פ"ו הלכות תרומה ה"ב) writes, תרומה של תורה אין אוכל אותה אלא כהן מיוחס – The Biblically obligated Terumah may only be given to a Kohen who is of pure lineage. It is also clearly inferred from the Yalkut Shimoni (פרשת קרח רמז תשנ"ה) how much more this is so in regards to Kodshim, the priestly portion of the sacrificial offerings, which only a Kohen of pure lineage may partake in.
This is the reason why there was a need for the laws of tzaraas to be given over to the Kohanim, so that they could know who it was that was inflicted with tzaraas, and it would thus be an indication to them that those inflicted were obviously מוציא שם רע, which is a sign that they must have some genealogical impurity in their lineage. This would thereby let the Kohanim know to stay away from intermarrying into those families, in order to keep themselves genealogically pure and eligible to receive all twenty-four priestly entitlements, including the Terumah and Kodshim.
We can now understand the Midrash that says; Moshe wondered, “Is this befitting the honor of my brother Aharon, to examine people’s tzaraas afflictions?”, to which Hashem replied, “And does he not receive the twenty-four priestly entitlements?”, for it is precisely because Aharon and the Kohanim were given the twenty-four priestly entitlements, that they were also given the responsibility to examine people’s tzaraas afflictions.
(זרע שמשון פרשת תזריע אות ז)
