Zevachim Daf 16 זבחים דַף 16

The Gemara provides three sources that עבודה performed by a זר is invalidated. Levi darshens וינזרו מקדשי בני ישראל – “and they [the Kohanim] shall separate themselves from the holies of Bnei Yisroel…and they shall not profane,” hinting that “Bnei Yisroel” (non-Kohanim) should separate themselves from performing avodah, and invalidate avodah they perform. Rebbe Yishmael says that if a בעל מום, who can eat kodashim meat, invalidates avodah he performs, then certainly a זר who cannot eat kodashim, invalidates avodah! Although the disqualification of בעל מום uniquely applies also to a korban itself, he ultimately says that אונן demonstrates otherwise, and although אונן is uniquely prohibited from eating maaser, a צד השוה – common factor is שמוזהרין ואם עבדו חיללו – that they are warned (not to perform avodah), and if they did avodah, they invalidated it, so the same applies to a זר. Rav Mesharshiya derived זר from יושב – one sitting while performing avodah, who may eat kodashim but invalidates avodah he performs. Although יושב is uniquely disqualified from testifying, a תלמיד חכם may testify while sitting. Even if we consider the general category of יושב stricter because most people cannot testify while sitting, a צד השוה can be derived from יושב and one of the above cases.

The Gemara provides four sources that an אונן invalidates avodah. (1) The Torah tells a Kohen Gadol, if a close relative dies, ומן המקדש לא יצא ולא יחלל – he need not leave the Mikdash, and he shall not profane, implying: הא אחר שלא יצא חילל – but someone else (a כהן הדיוט) who did not leave (but performed avodah) invalidates it. (2) Rebbe Elazar says that when the שעיר ראש חודש was burned on the day נדב and אביהוא died, Aharon said to Moshe: הן הקריבו – “Did they (אלעזר and איתמר) sacrifice it, while they were אוננים for their brothers? No, אני הקרבתי – I sacrificed it,” (and a Kohen Gadol brings korbanos as an אונן). מכלל דאי אינהו אקריב שפיר אישתרוף – [This defense] implies that had they sacrificed it, it was proper that [the חטאת] was burned, because a korban brought by an אונן is invalid. (3) A Baraisa of Rebbe Yishmael’s yeshiva derives אונן from a צד השוה between בעל מום, זר, and טמא, all of which are prohibited from avodah and invalidate avodah they perform. (4) Rav Mesharshiya derives אונן from יושב – one sitting while performing avodah, the same way he did earlier regarding זר.

Rava said that an אונן’s avodah is only invalid for a private korban, אבל בקרבן צבור מרצה – but regarding a communal korban, it effects acceptance, based on a kal vachomer from טומאה: if tumah, for which no exception is made for a Kohen Gadol regarding a קרבן יחיד, yet a קרבן ציבור may be offered by a כהן הדיוט in a state of tumah, then אנינות, which is permitted for a כהן גדול for (even) a קרבן יחיד, certainly would be excluded from its disqualification for a קרבן ציבור!? This kal vachomer is based on three suppositions of the laws in the above cases. Rava bar Ahilai argued that every one of these laws can be questioned based on restructuring the kal vachomer. Therefore, he concludes: אלא איכא למיפרך הכי ואיכא למיפרך הכי – rather, it possible to ask [a kal vachomer] this way, and it is possible to ask [a kal vachomer] that way, leading to contradictory laws. Instead, כל חדא וחדא תיקו בדוכתיה – every one of these laws should remain in its place, how it would apply without a kal vachomer, and no kal vachomer should be made.