Horayot 3B

או דלמא [ידיעה] דההוא בית דין דהורו בעינן! תיקו.

Or perhaps, for liability we require the awareness of the same court that issued the ruling, and that court no longer exists. The Talmud concludes: The dilemma should stand unresolved.

אמר רבי יונתן: מאה שישבו להורות ⁠– אין חייבין עד שיורו כולן, שנאמר: ״ואם כל עדת ישראל ישגו״, עד שישגו כולן [עד שתפשוט הוראה בכל עדת ישראל] אמר רב הונא בריה דרב הושעיא: הכי נמי מסתברא, דבכל התורה כולה קיימא לן רובו ככולו, והכא כתיב ״כל העדה״⁠ – הואיל וכך, אפילו הן מאה.

§ R' Yonatan says: Even in the case of 100 judges who convened to issue a ruling and erred, they are not liable to bring an offering unless they all issue that ruling, as it is stated with regard to liability to bring the offering: “And if the entire assembly of Israel should act unwittingly” (Leviticus 4:13). From the term “entire” it is derived that the judges are not liable until they all act unwittingly, and the ruling must disseminate and be adopted throughout the entire assembly of Israel, i.e., the Sanhedrin. Rav Huna, son of Rav Hoshaya, said: So too it is reasonable to conclude this, as throughout the entire Torah we maintain the principle: The legal status of the majority of an entity is considered like all of that entity, and here: “The entire assembly,” is written. Since it is so, a majority does not suffice. Even if they are 100 judges, they are liable only if the erroneous ruling was unanimous.

[תנן: ] הורו בית דין, וידע אחד מהן שטעו, או תלמיד וראוי להוראה, והלך ועשה על פיהם, בין שעשו ועשה עמהן, ובין שעשו ועשה אחריהן, ובין שלא עשו ועשה ⁠– הרי זה חייב, מפני שלא תלה בבית דין.

We learned in the Mishnah: If the court issued that ruling, and one of the judges knew that they erred, despite the fact that the majority ruled against his opinion, or if he was a student and was qualified to issue halakhic rulings, and that judge or student proceeded and performed that transgression on the basis of the court’s ruling, then whether the judges performed the transgression and he performed it with them, or whether the judges performed the transgression and he performed it after them, or whether the judges did not perform the transgression and he performed it alone, in all these cases the judge or the student is liable to bring an offering. This is due to the fact that he did not associate his action with the ruling of the court.