Bava Metzia 14A

חדא הוא, דחד טעם הוא, דמשום דקאמר רבי אלעזר מחלוקת בשאין חייב מודה ⁠– הוא מתרץ הכי.

The Talmud answers: It is actually one element, as both elements have the same one reason; because R' Elazar says that the dispute in the Mishnah is in a case when the liable party does not admit his debt, he explains R' Meir’s opinion in this manner, i.e., that a promissory note that does not include a property guarantee cannot be used to collect the debt even from unsold property.

תיובתא דשמואל בתרתי: חדא כרבי אלעזר, דהא מוקי מתניתין בשאין חייב מודה.

The Talmud elaborates on the statement that the baraita serves as a conclusive refutation of two elements of the opinion of Shmuel: One element is like the element of the opinion of R' Elazar that was refuted, as Shmuel also establishes the dispute in the Mishnah as referring to a case when the liable party does not admit to the debt, and the baraita states that in such a case there is no dispute.

וחדא דאמר שמואל: מצא שטר הקנאה בשוק ⁠– יחזיר לבעלים, ולא חיישינן לפרעון.

And the other one is that which Shmuel says: If one found a deed of transfer in the marketplace, in which it is stipulated that the debtor transfers the rights to his property from the date that the document was signed, he must return it to its owner, and we do not suspect that there was repayment and that there is collusion between the creditor and the debtor.

תיובתא דקתני הכא: אף על פי ששניהם מודים לא יחזיר לא לזה ולא לזה, אלמא חיישינן לפרעון, וכל שכן הכא דלא מודה לוה ⁠– דחיישינן לפרעון.

There is a conclusive refutation of that statement as well, as the baraita here teaches: Even if they both agree, he should return it neither to this person nor to that person. Apparently, we suspect that there was repayment. And all the more so here, in the case of a deed of transfer, when the liable party does not admit that he owes money, the deed should certainly not be returned, as we suspect that there was repayment.