(Mishnah): If the Great Sanhedrin (which is simply called Beis Din in this Masechta) (mistakenly) gave a Hora'ah (a ruling) to transgress a Mitzvah (punishable by Kares for one who was Mezid):

If an individual relied on Beis Din and transgressed (b'Shogeg), whether he transgressed with them, or after them, or even if Beis Din themselves did not transgress, he is exempt, because he relied on Beis Din.

If a member of the Beis Din or a Chacham qualified to give Hora'ah knew that Beis Din erred, and transgressed, whether he transgressed with them, after them, or without them, he is liable (brings a Korban), because he did not rely on Beis Din.

The general rule is, one who relies on himself is liable. One who relies on Beis Din is exempt.

Version #1 (Gemara - Shmuel): Beis Din brings Par He'elam Davar (a bull to atone for a mistaken Hora'ah that caused the majority of Yisrael to transgress) only if Beis Din said 'you are permitted.' (NOTE: Tana'im argue (4b-5a) about whether (also or only) the Shevatim (tribes) bring bulls. In general, we will say 'Beis Din brings a Par', without concern for the different opinions.)

(Rav Dimi of Neharde'a): Beis Din is liable only if they said 'you are permitted La'asos (to do)';

If they did not say this, the Hora'ah was not final.

Support #1 (for Rav Dimi - Abaye - Mishnah): If a Zaken Mamrei (a Chacham who ruled unlike the Sanhedrin) returned to his city, learned and taught like before, he is exempt;

If he ruled La'asos, he is killed.

Support #2 (R. Aba - Mishnah): (One witness testified that Leah's husband died. Beis Din told her that she may remarry.) If Leah was Mezanah (had relations without marriage), and her husband returned, she brings a Korban, for Beis Din allowed her only to remarry. (Rashi - they did not say 'you are permitted', therefore it is not considered Hora'ah. Ramah (in Tosfos ha'Rosh) - even though permission to remarry shows that she is (according to Beis Din) single and exempt for Zenus, still she is liable. This shows that Hora'ah is limited to the action that Beis Din permitted.)

Support #3 (Ravina - Mishnah): If Beis Din gave a Hora'ah to transgress...

One cannot refute this support.

Version #2 (Shmuel): Beis Din is liable only if they said 'you are permitted La'asos';

(Rav Dimi of Neharde'a): Even 'you are permitted' is a final Hora'ah.

Question #1 (against Rav Dimi - Abaye - Mishnah): If the Chacham returned to his city, learned and taught like before, he is exempt;

If he ruled La'asos, he is killed.

Question #2 (R. Aba - Mishnah): If Beis Din permitted Leah to remarry; she was Mezanah, and her husband returned, she brings a Korban, for Beis Din permitted only her to remarry.

Question #3 (Ravina - Mishnah): If Beis Din gave a Hora'ah to transgress...

One cannot answer this question.

(Mishnah): If an individual transgressed b'Shogeg according to Beis Din...

Question: The Mishnah should say 'if an individual transgressed according to Beis Din.' Why must it say 'b'Shogeg'?

Version #1 - Answer #1 (Rava): 'B'Shogeg' is when Beis Din permitted Chelev (forbidden fats), and an individual (wanted to eat other meat and) mistakenly ate Chelev;

'According to Beis Din' is simply relying on Beis Din (he knowingly ate Chelev).

Version #2 - Answer #1 (Rava): He is exempt only if his mistake was relying on Beis Din (he knowingly ate Chelev);

If he mistakenly ate Chelev, he is liable. (end of Version #2)

Rami bar Chama was unsure of this law.

Question (Rami bar Chama): If Beis Din permitted Chelev, and an individual mistakenly ate Chelev, what is the law?

Version #1 - Answer (Rava): We learn from extra words in the Mishnah. It says 'if an individual transgressed b'Shogeg, according to Beis Din';

This includes this case (he is exempt).

Rejection: Perhaps this teaches that he is exempt only when his mistake was relying on Beis Din (he knowingly ate Chelev), but if he mistakenly ate Chelev, he is liable!

Version #2 - Answer (Rava): We learn from extra words in the Mishnah. It says 'if an individual transgressed b'Shogeg, according to Beis Din';

This teaches that he is exempt only when his mistake was relying on Beis Din (he knowingly ate Chelev), but if he mistakenly ate Chelev, he is liable!

Rejection: Perhaps it teaches that he is exempt in either case, whether he mistakenly ate or relied on Beis Din. (end of Version #2)

Other Amora'im argued according to the two versions of Rava.

(Rav): If Beis Din permitted Chelev, and Reuven mistakenly ate Chelev, he is exempt;

(R. Yochanan): He is liable.

Question (against R. Yochanan - Beraisa): "From the common people" excludes a Mumar;

R. Shimon ben Yosi expounds "(if the Nasi... transgresses one of the Mitzvos... ) that one may not do, b'Shogeg, and is guilty. Or if he finds out" - one who would not have sinned knowingly brings a Korban. One who would have sinned knowingly does not bring a Korban;

No other verse is needed to exclude a Mumar! (This refutes R. Yochanan. Since Beis Din permitted it, Reuven would have eaten it even had he known that it is Chelev!)

Answer (Rav Papa): Since Beis Din would have retracted had they realized their mistake (and then Reuven would not have eaten knowingly), this is considered that he would not have eaten it knowingly.

(Rava): Rav admits that Reuven is not counted towards a majority (of Yisrael) who transgressed according to Beis Din.

Question: What is the reason?

Answer: "Bi'Shgagah" - (the full majority) must all commit the same mistake (relying on Beis Din).

(Mishnah): Whether he transgressed with Beis Din...

Question: Why must the Mishnah teach three cases (transgressing with Beis Din, after Beis Din, and without Beis Din)?

Granted, in the Reisha (first clause, in which he is exempt), each case is a bigger Chidush than the previous case.

However, in the Seifa, when he is liable, each case is a smaller Chidush than the previous one. They should have been taught in the reverse order!

Answer: Indeed, the Mishnah teaches the biggest Chidush, and then the smaller Chidushim!

(Mishnah): If a member of the Beis Din or a Chacham qualified to give Hora'ah...

Question: Why must it teach both of these?

Answer (Rava): One might have thought that he is liable (if he knew that Beis Din erred, and he transgressed) only if he is Gamir (learned; Rashi- learned the matter) and Savir (he can learn one matter from another through analysis), but Gamir or Savir is not enough. The Mishnah teaches that this is not so.

Question (Abaye): A Chacham qualified to give Hora'ah must be Gamir and Savir!

Answer (Rava): True! The Mishnah taught an extra clause to teach that he is liable even if he is only Gamir or Savir.

(Mishnah): If he is qualified to give Hora'ah...

Question: What is an example of someone qualified to give Hora'ah?

Answer (Rava): Shimon ben Azai and Shimon ben Zoma are qualified.

Question (Abaye): Surely, either of them would know the law. If he transgressed he would be Mezid. He would not bring a Korban!

Counter-question (Rava - Beraisa): "Ba'Asosah Achas (in transgressing one Mitzvah)" - an individual who relies on himself is liable, one who relies on Beis Din is exempt;

Suggestion: If Beis Din permitted Chelev, and one of them, or a Talmid who sits in front of them and is qualified to give Hora'ah, such as Ben Azai or Ben Zoma, knew that this is a mistake, perhaps he is exempt if he follows the Hora'ah of Beis Din!

"Ba'Asosah Achas" teaches that this is not so.

Answer (Rava (Tosfos; Rashi - Abaye): (Surely, Ben Azai knows the law.) We must say that he mistakenly thought that it is a Mitzvah to follow the Hora'ah of the Beis Din, even if it is wrong.

Answer (Rava): Likewise, the Mishnah discusses a Chacham like Ben Azai. He brings a Korban if he mistakenly thought that it is a Mitzvah to follow a mistaken Hora'ah of Beis Din!

(Mishnah): The general rule is, one who relies on himself (is liable)...

Question: What does this come to include?

Answer: It includes one who (normally) rejects the Hora'ah of Beis Din.

(Mishnah): One who relies on Beis Din is exempt.

Question: What does this come to include?

Answer: It includes if Beis Din gave a Hora'ah and later retracted (and Reuven did not hear the retraction, and acted according to the Hora'ah).

Objection: The continuation of our Mishnah (3b) explicitly teaches that!

Answer: Yes, it explains what was hinted at in our Mishnah.

(Rav Yehudah citing Shmuel): Our Mishnah is like R. Yehudah, but Chachamim obligate an individual who relies on Beis Din.

Question: What is the source that R. Yehudah exempts?

Answer (Beraisa #1): "If one soul will sin b'Shogeg in doing" - these are 3 exclusions (exemptions from bringing a Korban, for one who did half the sin, one who had a partner in the act, and) one who relied on Beis Din. (We will explain later how we know that this is like R. Yehudah.)

Question: What is the source that Chachamim obligate?

Answer (Beraisa #2) Suggestion: Perhaps if the minority of Yisrael sinned, they are liable, for Beis Din does not bring Par He'elem Davar for them, but if the majority sinned, they are exempt, for Beis Din brings a Par for them;

Rejection: "From the common people" - even the majority, and even all of them (are liable).

Question: What is the case?

Suggestion: They transgressed b'Shogeg (not due to a Hora'ah).

Rejection: If so, Beis Din does not bring a Par!

Answer #1: Rather, they relied on a Hora'ah of Beis Din.

Rejection: "From the common people" discusses transgressing b'Shogeg!

Answer #2: Rather, the Beraisa means as follows. If the minority of Yisrael sinned b'Shogeg, they bring Chata'os (sin-offerings), for Beis Din (when they give a mistaken Hora'ah) do not bring a Par for them (a minority who sinned due to the Hora'ah);

Suggestion: If the majority sinned b'Shogeg, perhaps they are exempt, for Beis Din brings a Par for them (when their mistaken Hora'ah caused the majority to sin)!

Rejection: "From the common people" teaches that even if the majority or all of Yisrael sin, they bring Chata'os.

Question (Rav Papa): We need not explain that way. We can say that when the minority sinned due to a mistaken Hora'ah of Beis Din, neither they nor Beis Din bring a Korban!

Rejection: If so, why does the Tana use the verse to teach that the majority brings when they sin? He should first prove that the minority brings!

Rather, when the minority sin due to a Hora'ah, each brings a Kisvah or Se'irah (female lamb or goat). We already know that they bring the same for transgressing b'Shogeg;

Therefore, the verse teaches about the majority.

Question: Both Beraisos are anonymous. How did Shmuel know that Beraisa #1 is like R. Yehudah, and Beraisa #2 is like Chachamim? Perhaps they are just the opposite!

Answer #1: R. Yehudah often expounds multiple exclusions from one verse.

(Beraisa - R. Yehudah): "This is the law of the Olah (burnt offering), it is" are three exclusions.