וכי תימא פליגי רבנן עליה דרשב"ג והאמר רבי אבהו שנים שדנו לדברי הכל אין דיניהם דין גברא אגברא קא רמית
And if you would say the Rabbis disagree with Rabban Shimon ben Gamliel with regard to the minimum number of judges necessary to adjudicate, but doesn’t Rabbi Abbahu say: With regard to a court of two judges that adjudicated cases of monetary law of any type, which would include cases of admissions and loans, everyone agrees that their judgment is not a valid judgment, as a court with fewer than three judges is invalid? The Gemara rejects this question: Are you setting the statement of one man against the statement of another man? Although Rabbi Abbahu asserts that all agree that two judges cannot issue a binding judgment, Shmuel differs. According to Shmuel, the Rabbis hold that the judgment of two judges is considered binding.
גופא א"ר אבהו שנים שדנו דיני ממונות לדברי הכל אין דיניהם דין איתיביה רבי אבא לרבי אבהו דן את הדין וזיכה את החייב וחייב את הזכאי טימא את הטהור טיהר את הטמא מה שעשה עשוי ומשלם מביתו
§ Since it was mentioned incidentally, the Gemara discusses the matter itself: Rabbi Abbahu says: With regard to a court of two judges that adjudicated cases of monetary law of any type, which would include cases of admissions and loans, everyone agrees that their judgment is not a valid judgment. Rabbi Abba raised an objection to Rabbi Abbahu from a mishna (Bekhorot 28b): If a single judge adjudicated a case of monetary law and erroneously exonerated the litigant who should have been deemed liable, or deemed liable the litigant who should have been deemed exempt, or if one issued a halakhic ruling whereby he deemed ritually impure that which is actually pure, or deemed pure that which is impure, what he did is done, i.e., his ruling is binding. And the judge nevertheless pays from his house, i.e., from his own pocket, for the loss he has caused. Evidently, the ruling of even a single judge constitutes a valid judgment.
הכא במאי עסקינן דקיבלוהו עלייהו אי הכי אמאי משלם מביתו דאמרו ליה דיינת לן דין תורה
The Gemara responds: Here we are dealing with a case in which the litigants accepted the singular judge upon themselves, and it is for that reason that his ruling is binding. Otherwise, it would not be binding, as a halakhic court must contain a minimum of three judges. The Gemara asks: If so, that the litigants agreed to accept whatever ruling the judge issued, why must the judge pay from his own house? The Gemara answers: The judge is liable because the case is where they said to him: Adjudicate the case for us according to Torah law. Since he did not issue a halakhically proper judgment, he is liable.
א"ל רב ספרא לרבי אבא דטעה במאי אילימא דטעה בדבר משנה והאמר רב ששת א"ר (אמי) טעה בדבר משנה חוזר אלא דטעה בשיקול הדעת
Rav Safra said to Rabbi Abba: This ruling applies when he erred in what respect? If we say that he erred in a matter that appears in the Mishna, and he mistakenly ruled against an explicitly stated halakha, that is difficult. But doesn’t Rav Sheshet say that Rabbi Ami says: If the judge erred in a matter that appears in the Mishna, the decision is revoked and the case retried? Rather, the case is where he erred in his deliberation.
היכי דמי בשיקול הדעת אמר רב פפא כגון תרי תנאי ותרי אמוראי דפליגי אהדדי ולא איתמר הלכתא לא כמר ולא כמר וסוגיין דעלמא אליבא דחד מינייהו ואזל איהו ועבד כאידך היינו שיקול הדעת
The Gemara asks: What are the circumstances of an error in deliberation? Rav Pappa said: The circumstances of an error in deliberation are where, for example, there are two tanna’im or two amora’im who disagree with one another, and the halakha was not stated in accordance with the opinion of one Sage or with the opinion of the other Sage; and the standard practice is in accordance with the opinion of one of them, and he went and executed the judgment in accordance with the other opinion; this is an error in deliberation.
לימא כתנאי ביצוע בשלשה דברי ר"מ וחכ"א פשרה ביחיד סברוה לכ"ע מקשינן פשרה לדין
§ The Gemara suggests: Let us say that the dispute between Shmuel and Rabbi Abbahu about a court composed of two judges is parallel to a dispute between tanna’im, as detailed in the following baraita: Mediation can be performed by a panel of three judges; this is the statement of Rabbi Meir. And the Rabbis say: Compromise can be performed by even a single judge. The Sages assumed that everyone agrees that we compare compromise to judgment, and require the same amount of judges for each process.
מאי לאו בהא קמיפלגי דמר סבר דין בשלשה ומר סבר דין בשנים לא דכ"ע דין בשלשה והכא בהא קמיפלגי דמר סבר מקשינן פשרה לדין ומר סבר לא מקשינן פשרה לדין
What, is it not that they disagree in this matter, that one Sage, Rabbi Meir, holds that judgment and compromise can be performed by a minimum of three judges, and one Sage, the Rabbis, holds that judgment and compromise can be performed even by two judges? The Gemara rejects this analysis: No, it is that everyone holds that judgment must be performed by a minimum of three judges, and here, they disagree with regard to this matter: One Sage, Rabbi Meir, holds that we compare compromise to judgment, and one Sage, the Rabbis, holds that we do not compare compromise to judgment.
לימא תלתא תנאי בפשרה דמר סבר בשלשה ומר סבר בשנים ומר סבר ביחיד אמר רב אחא בריה דרב איקא ואיתימא רבי יימר בר שלמיא מאן דאמר תרי אפילו חד נמי והאי דקאמר תרי כי היכי דליהוו עליה סהדי
The Gemara suggests: Let us say that there are three opinions of tanna’im with regard to mediation leading to compromise, as one Sage, Rabbi Meir, holds that mediation must be performed by a panel of three judges; and one Sage, Rabban Shimon ben Gamliel, holds that it can be performed by two judges; and one Sage, the Rabbis, holds that it can be performed by a single judge. The Gemara rejects this suggestion. Rav Aḥa, son of Rav Ika, and some say Rabbi Yeimar bar Shelamya, said: The one who says mediation must be performed by two judges would say that it may even be performed by one. And the reason that he says two is merely that there would be two witnesses to the proceedings, who could testify about them if necessary. In that way, neither side could later deny the terms of the compromise.
אמר רב אשי ש"מ פשרה אינה צריכה קנין דאי סלקא דעתך צריכה קנין למ"ד צריכה תלתא ל"ל תסגי בתרי וליקני מיניה והלכתא פשרה צריכה קנין
Rav Ashi says: Learn from that discussion that compromise does not require a formal act of acquisition, which would legally transfer rights to the settlement payment to the other party. As if it enters your mind that compromise requires an act of acquisition to finalize its terms, according to the one who says it requires an act of acquisition, why do I need a formal court of three judges? Let it suffice with two judges, and let one litigant perform an act of acquisition with the other litigant to signify their commitment to abide by the compromise. If a formal act is required to grant halakhic force to the compromise, there is no advantage to having a panel of three judges with the status of a formal court. The Gemara concludes: But nevertheless, the halakha is that a compromise requires an act of acquisition to finalize its terms.
תנו רבנן כשם שהדין בשלשה כך ביצוע בשלשה
§ The Sages taught in a baraita (Tosefta 1:2–8): Just as judgment is performed by three judges, so too, mediation is performed by three judges.