אם הכהן המשיח יחטא לאשמת העם. מִדְרָשׁוֹ: אֵינוֹ חַיָּב אֶלָּא בְּהֶעְלֵם דָּבָר עִם שִׁגְגַת מַעֲשֶֹה, כְּמוֹ שֶׁנֶּאֱמַר לְאַשְׁמַת הָעָם וְנֶעְלַם דָּבָר מֵעֵינֵי הַקָּהָל וְעָשׂוּ (שם); וּפְשׁוּטוֹ לְפִי אַגָּדָה: כְּשֶׁכֹּהֵן גָּדוֹל חוֹטֵא, אַשְׁמַת הָעָם הוּא זֶה, שֶׁהֵן תְּלוּיִין בּוֹ לְכַפֵּר עֲלֵיהֶם וּלְהִתְפַּלֵּל בַּעֲדָם, וְנַעֲשֶׂה מְקֻלְקָל: אם הכהן המשיח יחטא לאשמת העם IF THE PRIEST THAT IS ANOINTED DO SIN לאשמת העם — The Halachic explanation is that he is liable to bring a sin-offering only when there was ignorance of the real matter (of the law in question; i. e. after having considered the case in question he came to a wrong decision) together with a mistaken action (i. e. where he erred in a Halachic decision and as a result of this error acted against the true law), just as it is stated with reference to the guilt of the whole people): (v. 13) “[And if the whole congregation of Israel err] and the thing be hid from the eyes of the assembly and they have done [somewhat against the commandments of the Lord]" (Sifra, Vayikra Dibbura d'Chovah, Chapter 2 1; Horayot 7a; Rashi on v. 13). Its literal sense is according to the Agadic explanation: When the High-priest sins this is the guilt of the people (i. e. it results in the people remaining under a load of guilt), because they are dependent on him to effect atonement for them and to pray on their behalf, and now he himself has become degenerate and can thus not expiate for them, wherefor they remain under guilt.
פר. יָכוֹל זָקֵן, תַּלְמוּד לוֹמַר בֶּן, אִי בֶּן יָכוֹל קָטָן, תַּלְמוּד לוֹמַר פַּר, הָא כֵּיצַד? זֶה פַּר בֶּן שָׁלוֹשׁ (שם): פר A BULLOCK — One might think that it may be an old one! Scripture, however, adds בן, a young animal. If, then, it must be בן, a young one, I might think a very young animal is fitted too (this being also implied in the term בן)! Scripture, however, states פר! How is this to be reconciled? By explaining פר בן בקר to be a bullock of three years (which is neither too old nor too young) (Sifra, Vayikra Dibbura d'Chovah, Chapter 3 1; cf. Rashi on Leviticus 9:7 and Note thereon).