Ketubot 51B

יש בהן אחריות נכסים ⁠— לא יחזיר, שבית דין נפרעין מהן.

they include a property guarantee he may not return them to the lender, as he does not know who lost them. It is possible that the debt has already been paid and the documents were returned to the borrower, and he lost them. He may not give them back to the lender even if the borrower admits that he still owes the money, as the court collects the debt from purchasers of the borrower’s property. There is a concern that the borrower has repaid the loan and he is saying that he did not yet repay it because he has conspired with the lender to convince the court to confiscate liened property that the borrower sold, and the lender and borrower will divide the proceeds.

אין בהן אחריות נכסים ⁠— יחזיר, שאין בית דין נפרעין מהן, דברי רבי מאיר. וחכמים אומרים: אחד זה ואחד זה לא יחזיר, שבית דין נפרעין מהן.

If, however, the documents were of the kind that do not include a property guarantee he returns them, as in this case the court does not collect from purchasers of the borrower’s property. This is the statement of R' Meir. And the Rabbis say: In both this case and that one, he may not return the promissory notes, as the court collects from purchasers of the borrower’s property regardless, as it is assumed that the omission of the property guarantee from a document is merely a scribal error.

רישא רבי מאיר וסיפא רבי יהודה! וכי תימא כולה רבי מאיר היא, ושאני ליה לרבי מאיר בין כתובה לשטרי. ומי שאני ליה?

If so, the first clause of the Mishnah here is in accordance with the opinion of R' Meir, and the latter clause is in accordance with the opinion of R' Yehuda. And if you would say that the entire Mishnah is in accordance with the opinion of R' Meir, and there is a difference for R' Meir between a marriage contract and other documents, i.e., the guarantee of a marriage contract applies even if it is omitted but the property guarantee in other contracts does not, is there really a difference for him between the two types of documents?