[R. Hiyya had asked Rabbi whether Rav could] permit firstborn? [Rabbi answered:] He may not permit.
[Firstborn domestic animals must be given to a Kohen for Temple sacrifice. But if a judge ruled that it had a permanent blemish, the Kohen could eat it. By the time of Rabbi, there were no longer any Temple sacrifices, the firstborn would be allowed to pasture until a permanent blemish developed, after which it could be eaten.]
Why [would Rabbi not permit Rav to rule? If because he was not sufficiently wise -- we just said [see San 5a.3] that he _was_ very wise. Because he was not an expert on blemishes? But Rav said "I grew up among herders for eighteen months to know which were permanent blemishes and which were temporary blemishes" [so that he _was_ an expert]. Instead, it [Rabbi's decision not to permit Rav to rule on firtsborn's blemishes] was to give respect to Rabbah bar Hanna. [Rashi: The Babylonians had great respect for Rav. By giving Rabbah bar Hanna wider authority than Rav, Rabbi was ensuring that the Babylonians would also respect Rabbah bar Hanna.]
Alternatively, [Rabbi did not authorize Rav to rule on a firstborn's blemishes] precisely because of his expertise. Rav was an expert on blemishes, and would permit blemishes with which people were unfamiliar, and they might [make a mistake] and say that Rav permitted a particular kind of blemish, and come to permit even a temporary blemish [when only permanent blemishes could allow the non-sacred use of the firstborn].
[R. Hiyya had asked Rabbi whether Rav could] decide [on ritual matters]? [Rabbi answered:] He may decide.
If he has learned [the ritual laws], why does he need permission [to decide]? [Permission from the Exilarch or Patriarch to adjudicate in monetary cases was to protect the judge from lawsuits in case of error.]
[The gemara answers:] Because of an incident that occurred, as we learned in a b'raita: Once Rabbi traveled to a certain place and he saw people kneading dough in ritually impure [bowls]. Rabbi asked them why they were kneading dough in impure [bowls]. They said that a student had ruled for them that betza`im [pond] water does not [make the dough] susceptible to impurity [so that the ritual purity of the bowls was irrelevant].
Actually, he [the student] had ruled on betzim water but they thought he had said betza`im. [Betzim are eggs; betzim water is the watery portion of the egg, i.e., the albumin.]
Also, they (may have) erred in understanding the mishna [Parah 8:10 on water acceptable for use in the Red Heifer ritual]: Karmion and Figah [two rivers] water cannot be used because they are like betza`im water. But they thought that just like betza`im water cannot be used for purification, so they cannot make food susceptible for ritual impurity. [Water used for purification must be from a flowing source, and the Karmion and Figah rivers flowed so slowly that they were more like betza`im {ponds}.] But this is not the case: Water used for purification must be flowing, but any water [even betza`im water] makes food susceptible to impurity.
At that time [i.e., because of this mistake attributable to the student's lack of precision that led to the error], they ruled that a student cannot rule (on ritual matters) unless he obtains authorization from his teacher.
Tanhum b. R. Ami went to Hatar [a city] and taught that it was permitted to soak wheat on Pesach. [Rashi: the wheat was soaked, ground into flour and immediately baked, before there was a chance for it to leaven.] They [the residents of Hatar] said to him: Isn't R. Mani of Tzor [Tanhum's teacher] here? And was it not taught in a b'raita that a student cannot decide halakha in the presence of his teacher unless he is three parsa'ot away, corresponding to the size of the camp of Israel [in the wilderness]?
[Rashi: Ex 33:7 relates that the Israelites sought Moses' advice. Num 33:49 describes the encampment as stretching from Beit haYeshimot to Avel haShitim. And Rabbah bar bar Hana {Eruvim 55b} that he personally saw that this distance was three parsa'ot, about 9 miles.] He [Tanhum] answered: I did not know [that R. Ami was so close].
[The gemara's conclusion here is that a student cannot rule within 3 parsa'ot of his teacher. This rule apparently preceeded the rabbinic decree (in our previous text) against student's issuing any ruling without permission, with no limit of distance.]
R. Hiyya saw a man standing in a cemetery. He [R. Hiyya] said to him: Are you not the son of so-and-so the Kohen? [A kohen is not permitted to enter a cemetery.] He [the man] said: Yes. But my father was a man with raised eyes [Rashi: who followed his eyes, i.e., who was readily tempted], and he saw a divorced woman and disqualified [his son].
[A kohen cannot marry a divorcee, but if he does so, the marriage is valid. The son of such a union is not a kohen, but a halal, who enjoys neither the priviledges nor the restrictions of a kohen. Thus, the son was permitted to stand in a cemetery. Rashi explains that R. Hiyya was a student of Rabbi, who was presumably in the vicinity. But R. Hiyya nevertheless raised the halakhic question {equivalent to issuing a halakhic ruling} because a student is permitted to do so, even in the presence of his teacher, to stop or prevent a transgression.]
[The gemara raises a different issue:] Clearly partial [permission by a Nasi or Exilarch] is effective, as we learned [above, when Rabbi permitted Rav to rule, but not on matters of firstborn animals], but what about conditional permission [Rashi: for a limited period of time]?
Come learn: R. Yohanan said to Rav Shiman [Rashi: who was leaving for Babylonia]: You have our permission [to rule] until you return to us [i.e., time-limited permission is possible].
(Returning to the) basic issue, as we have learned (on San 3a): Shmuel said: If two judges have ruled [on a dispute involving a loan] their decision is binding, but it is called an "insolent court."
Rav Nachman was sitting and repeated this text, and [his desciple] Rava challenged Rav Nachman [citing a mishna on San 29a]: Even if two [judges] find in his favor, or two find him guilty, and the one says "I do not know," they add judges.
[The undecided judge is treated as if he were absent, and a third judge must rule. No matter how the third judge rules, the decision of the majority will be binding. Thus, the mishna there seems to imply the necessity that at least three judges should be present. This ends the citation to the mishna.]
But if so [i.e., if Shmuel's ruling that a decision of two judges is binding], let them be as two judges who ruled [and their decision is not binding because a third judge is absent].
[The gemara answers:] There [the mishna] is different, for they initially convened as a court of three, but here [Shmuel's ruling] they did not convene with the intention of making a court of three [so the unanimous decision of two judges is binding].
[Rava] objected: Rabban Shimon b. Gamliel says: A ruling must be by three [judges], but a compromise can be with only two. And a compromise is stronger than a ruling; if two rule, the litigants can retract [their agreement to accept the ruling], but if two judges (effect a) compromise, the litigants cannot retract their agreement (to accept it).
And if you argue that the Rabbis did not agree with Rabban Shimon b. Gamilel, didn't R. Abahu say that everyone agrees that the ruling of a court of two judges is not binding? [Shmuel, an amora, can only disagree with a tanna if he has a supporting tannaitic ruling, which, R. Abahu says, does not exist.]
[The gemara rejects this argument:] You are citing a contradiction between one person and another person (both Amoraim). [Rashi: R. Abahu indeed says that the Rabbis do not disagree with Rabban Shimon ben Gamliel. But Shmuel disagrees, and says that the Rabbis _do_ disagree, and that is the tannaitic source Shmuel needs to support his disagreement with the mishna.]
Returning to our subject, R. Abahu says: If two judges rule in monetary cases, everyone agrees that their verdict is not binding. R. Abba objected to R. Abahu [citing a mishna in Bechorot 28b]: If a judge ruled and absolved the guilty party, or ruled that the non-liable litigant was liable, or declared an impure item pure, or a pure item impure, what is done is done, and he [the judge] must make restitution from his own property. [This implies that even the ruling of a single judge is binding, which is inconsistent with R. Abahu'sruling.]
[The gemara answers:] This [the mishna] is a case in which the litigants accepted the judge (to rule) over them. [If they agreed in advance to accept his ruling, it is binding. But otherwise, R. Abahu's principle would apply, and the ruling would not be binding.]
If so [if the mishna is dealing with a case in which the litigants accepted the ruling], why must he (the judge) make resitution from his own assets?
Because they (the litigants) can say "Did you render a Torah judgment." [The litigants can say that they had agreed to accept a correct ruling; since the ruling was not correct, the judge is liable.]