Ketubot 94B

ושמואל דאמר כרבי אלעזר, דאמר: עדי מסירה כרתי.

And Shmuel said his ruling in accordance with the opinion of R' Elazar, who said that witnesses of the transmission effect the transaction, i.e., the act of transferring the legal document to the beneficiary causes the transaction to take effect. Therefore, the fact that the two documents bear the same date is of no consequence because the documents were presumably not given to their beneficiaries simultaneously, and the property belongs exclusively to the individual who received his document first. Consequently, there is no reason to divide the property.

לא, דכולי עלמא כרבי אלעזר, והכא בהא קמיפלגי, רב סבר: חלוקה עדיפא. ושמואל סבר: שודא דדייני עדיפא.

The Talmud responds: No, it is possible to say that everyone holds in accordance with the opinion of R' Elazar, and here they disagree about the following: Rav holds that in a case of a doubt that cannot be resolved with regard to monetary law, division is preferable, and Shmuel holds that leaving the decision to the discretion of the judges is preferable.

ומי מצית מוקמת ליה לרב כרבי אלעזר? והאמר רב יהודה אמר רב: הלכה כרבי אלעזר בגיטין. כי אמריתה קמיה דשמואל, אמר: אף בשטרות. מכלל דרב סבר בשטרות לא! אלא: מחוורתא רב כרבי מאיר, ושמואל כרבי אלעזר.

The Talmud asks: Can you really establish that the opinion of Rav is in accordance with the opinion of R' Elazar? Didn’t Rav Yehuda say that Rav said: The halakha is in accordance with the opinion of R' Elazar with regard to bills of divorce? And Rav Yehuda related further: When I said this halakha in the presence of Shmuel, he said: The halakha is in accordance with the opinion of R' Elazar even with regard to other legal documents as well. By inference, it is apparent that Rav holds that with regard to other legal documents, no, the halakha is not in accordance with R' Elazar. Rather, it is clear that Rav holds in accordance with the opinion of R' Meir, and Shmuel holds in accordance with the opinion of R' Elazar.