Ketubot 79A

אתאי לקמיה דרב נחמן, קרעיה רב נחמן לשטרא. אזל רב ענן לקמיה דמר עוקבא, אמר ליה: חזי מר נחמן חקלאה היכי מקרע שטרי דאינשי. אמר ליה: אימא לי איזי, גופא דעובדא היכי הוה?

The mother came before Rav Naḥman for judgment. Rav Naḥman tore the document, accepting her claim that she did not intend to transfer ownership of her property. Rav Anan went before Mar Ukva, the Exilarch, and said to him: Let the Master observe Naḥman the farmer, how he tears people’s documents. Rav Anan was upset that Rav Naḥman destroyed a legitimate document. Mar Ukva said to him: Tell me, please, what was the actual incident?

אמר ליה: הכי והכי הוה. אמר ליה: שטר מברחת קא אמרת? הכי אמר רב חנילאי בר אידי אמר שמואל: מורה הוראה אני: אם יבא שטר מברחת לידי ⁠— אקרענו.

Rav Anan said to Mar Ukva: This and that transpired; i.e., he apprised him of all the details. Mar Ukva said to him: Are you saying it was a document of evasion? This is what Rav Ḥanilai bar Idi said that Shmuel said: I am an authority who issues rulings and have issued the following directive: If a document of evasion comes to my hand, I will tear it, as it is clear that it was not intended for the actual transfer of property but merely to distance it from someone else.

אמר ליה רבא לרב נחמן: טעמא מאי? דלא שביק איניש נפשיה ויהיב לאחריני. הני מילי לאחריני, אבל לברתה יהיבא! אפילו הכי: במקום ברתה, נפשה עדיפא לה.

After seeing Rav Naḥman tear the document, Rava said to Rav Naḥman: What is the reason for your actions? Is it that you assume that it was not a wholehearted gift because a person does not abandon his own interests and give a gift to others? That applies only when it is given to others who are strangers, but to her daughter a mother would give property wholeheartedly. Rav Naḥman replied: Even so, where her interests clash with those of her daughter, her own interests are preferable to her, and therefore she did not intend to waive her rights.