אָדָם כִּי יִהְיֶה בְעוֹר בְּשָׂרוֹ שְׂ אֵת אוֹ סַפַּחַת וגו' וְהוּבָא אֶל אַהֲרֹן הַכֹּהֵן אוֹ אֶל אַחַד מִ בָּנָיו הַכֹּהֲנִים (יג, ב)
If a man has a se’eis, a sapachas, or a baheres on the skin of his flesh, and it forms a spot of tzoraas on the skin of his flesh... (13:2)
Chazal (Negaim 3:1 and Toras Kohanim, end of Perek 1 of Negaim) learn from this verse that anyone can examine negaim but declaring them tamei or tahor can only be done a kohen. If those who examine it determine that it is tamei, they tell the kohen to say the word “tamei”, and he must say it to validate the tumah. If they determine that it is tahor, they must tell the kohen to say the word “tahor”.
Rav Dovid of Tolna zy”a uses this rule to explain the statement of Chazal (Medrash Tehillim 1) that Dovid Hamelech prayed that one who recites Tehillim should be considered equal to one who studies Negaim and Ohalos. He explains this to mean that Dovid requested of Hashem that if even a simple person – who does not understand the meaning of the words – recites Tehillim, it should be effective just like when a simple kohen, who doesn’t understand the rules of negaim, says the word “tamei” or “tahor”.
