Bava Batra — Daf 106b

אמר ליה הויא עשרין גריוי משחיה ולא הואי אלא חמיסרא אתא לקמיה דאביי אמר ליה סברת וקבילת

והתנן פחות משתות הגיעו עד שתות ינכה הני מילי היכא דלא קים ליה בגוה אבל היכא דקים ליה בגוה סבר וקביל

והא עשרין אמר לי אמר ליה דעדיפא כעשרין

תניא ר' יוסי אומר האחין שחלקו כיון שעלה גורל לאחד מהן קנו כולם מ"ט אמר ר' אלעזר כתחלת ארץ ישראל מה תחלה בגורל אף כאן בגורל

אי מה להלן בקלפי ואורים ותומים אף כאן בקלפי ואורים ותומים אמר רב אשי בההוא הנאה דקא צייתי להדדי גמרי ומקנו להדדי:

איתמר שני אחין שחלקו ובא להן אח ממדינת הים רב אמר בטלה מחלוקת ושמואל אמר מקמצין

אמר ליה רבא לרב נחמן לרב דאמר בטלה מחלוקת אלמא הדר דינא אלא מעתה הני בי תלתא דקיימי ואזול בי תרי מינייהו ופלוג הכי נמי דבטלה מחלוקת

הכי השתא התם נחיתי אדעתא דבי תלתא מעיקרא הכא לא נחיתי אדעתא דבי תלתא מעיקרא

אמר ליה רב פפא לאביי לשמואל דאמר מקמצין למימרא דקם דינא והא רב ושמואל דאמרי תרוייהו כור בשלשים אני מוכר לך יכול לחזור בו אפילו בסאה האחרונה כור בשלשים סאה בסלע אני מוכר לך ראשון ראשון קנה

who stated  that it contained an area of twenty griva,  but it contained only fifteen. He  came before Abaye who said unto him, '[Surely] you realized [its size] and accepted.' But did we not learn: THE SALE IS VALID [IF THE DIFFERENCE IS] LESS THAN A SIXTH; [IF IT AMOUNTS] TO A SIXTH, DEDUCTION  MUST BE MADE? — This applies only where [the buyer] is not acquainted with the field, but where he is acquainted with it [it is assumed that] he understood [the conditions] and accepted. 'But,' [argued R. Papa.] 'he said to me, twenty!'  — He replied: '[The seller might say that he meant] that the field was as good  as [one of] twenty. It was taught: R. Jose said: When brothers divide [an estate]  all of them acquire  possession [of their respective shares] as soon as the lot for one of them is drawn.  On what ground [is possession acquired]? — R. Eleazar said: [Possession is acquired in the same way] as [at] the beginning of [the settlement of] the land of Israel. As [at that] beginning, [the acquisition was] by lot, so here [also it is] by lot. Since there, however, [the division was made] through the ballot box  and the Urim and Tummim,  [should not the division] here also [be made] through  the ballot box and the Urim and Tummim? — R. Ashi replied: [The lot alone suffices here] because [in return for] the benefit of mutual agreement  they determine to allow each other to acquire possession [by the lot  alone]. It has been stated: [In the case when] two brothers divided [an estate between them] and a [third] brother arrived from a country beyond the sea, Rab said the division is cancelled,  and Samuel said they relinquish  [thirds from their respective shares for the third brother]. Raba said to R. Nahman: According to Rab, who said that the division is cancelled, it is clear that [we act on the principle that even a definite] decision may be revised; but if so, the division should be cancelled  also in the case where [a partnership] of three was in existence and two of these divided  the property!  — What a comparison! There,  they went [into the matter], from the very beginning, with the intention of [dividing the property between] three;  but here,  they did not enter '[into the matter], at first, with the intention of [dividing the estate between] three. R. Papa said to Abaye: According to Samuel, who said that they relinquish [thirds from their respective shares for the third brother], it appears that [where] a decision [has been arrived at, it] must be adhered to; but, surely, both Rab and Samuel have said:  [If the seller said.] 'I sell you a kor for thirty', he may withdraw even at the last se'ah;  [if, however, he said,] 'I sell you a kor for thirty. [each] se'ah for a sela' [the buyer] acquires  possession of every se'ah as it is measured out for him.  [This shows that even a decision arrived at,  may be upset!]