Bava Batra 52B

כדשלח רב הונא בר אבין: דברים העשוין להשאיל ולהשכיר, ואמר ״לקוחין הן בידי״, אינו נאמן! קשיא.

As Rav Huna bar Avin sent a ruling: If one other than the one previously established to be the owner is in possession of items that are typically lent or rented, and says: They are purchased, and that is why they are in my possession, he is not deemed credible. In this case as well, as the father of the orphans could not be awarded these documents without bringing proof, the same should be true of his orphans. Why, then, would Rav concede to Shmuel? The Talmud concedes: This is difficult.

אמר רב חסדא: לא שנו אלא דאין חלוקין בעיסתן, אבל חלוקים בעיסתן ⁠– אימור מעיסתו קימץ.

Rav Ḥisda says: They, i.e., Rav, taught his ruling, that the brother must bring proof that he owns the property listed in the documents that appear under his name, only when they do not divide any of their property, even with regard to their dough, i.e., they share everything, even their food. But if they divide with regard to their dough, say that this brother removed money from his dough, i.e., reduced his expenses for food, thereby amassing his own property.

ראיה במאי? רבה אמר: ראיה בעדים, רב ששת אמר: ראיה בקיום השטר.

With regard to the requirement that proof be brought, the Talmud asks: With what is one considered to have brought proof? Rabba says: Proof is brought with the testimony of witnesses that he purchased the property listed in the document or granted the loan with his own money or that he inherited it from his mother’s family. Rav Sheshet says: Proof is brought with the court’s ratification of the document in which his name appears.

אמר ליה רבא לרב נחמן: הא רב והא שמואל, הא רבה והא רב ששת; מר – , כמאן סבירא ליה? אמר ליה: אנא מתניתא ידענא, דתניא: אחד מן האחין שהיה נותן ונושא בתוך הבית, והיו אונות ושטרות יוצאין על שמו, ואמר: שלי הן, שנפלו לי מבית אבי אמא ⁠– עליו להביא ראיה.

Rava said to Rav Naḥman: This is the opinion of Rav and this is the opinion of Shmuel; this is the opinion of Rabba and this is the opinion of Rav Sheshet. In accordance with whose opinion does the Master hold? Rav Naḥman said to him: I know a baraita, which is the source of my opinion, as it is taught (Tosefta 9:2): In a case where there was one of the brothers who was engaging in commerce in the house, managing the family finances, and there were bills of sale and other documents circulating with his name appearing as the owner of the property or as a lender, and that brother said: The money and property are mine, as they fell to me as an inheritance from the house of the father of my mother, who is not the mother of the other brothers, it is upon him to bring proof of ownership.