לזכות ידיד נפשי, איש התורה, התפילה והחסד הרב יהושע דניאל בן פרידה שמחה וכל ב"ב לברכה והצלחה בכל מעשי ידיהם
The gemara in Bava Metzia [7a] says in the name of Rebbi that if a lender and borrower are both holding on to a loan document and each one contends that it belongs to him alone [the lender says that the loan is still due while the borrower says that it is not], the law is that the shtar should be "established with it's signatures".
The gemara understands this cryptic remark to mean that the shtar is validated and the lender gets to collect with it. The gemara wonders in wonderment of wonders "What, Rebbi doesn't accept what the mishna [2a] teaches that if two people are holding on to a garment we split it 50-50?"
Ad kan! [See there for the development of this exciting sugya - what sugya is NOT exciting??]
Six wonders on the gemara's wonder...
1] Maybe Rebbi holds like Rebbi Yosi [later in the sugya] that we don't assume a loan has been paid unless we know otherwise [לא חיישינן לפירעון]?
2] Maybe the case is one where the loan is not yet due, so why would we assume that it was paid at all?
3] Maybe here is different than the mishna because in our case there is a מרא קמא - it is safe to assume that the document was originally in the hands of the lender and therefore should be returned to him unlike the mishna where there is no מרא קמא?
4] Maybe here is different than the mishna because one of them is DEFINITELY lying while in the case of the mishna maybe they picked the garment up simultaneously and there is no definite liar?
5] Why do we have to resort to the mishna - the gemara could have asked simply that it is not right to give the lender everything when maybe the shtar fell from the hands of the borrower?
6] Maybe ..... Rebbi argues with the mishna? He is allowed to have a different opinion - he is a Tanna?!
Thoughts Torah scholars??? Think, look up in sefarim, ask your chavrusos, Rabbeim, co-workers, wives, mothers, fathers, children, dentists etc.