1. מודה במקצת requires admitting to a defined amount (בית זה vs. עד הזיז)

The Mishnah on the previous Daf stated: אין נשבעין אלא על דבר שבמדה ושבמשקל ושבמנין – one only swears about something defined by measurement, weight, or number; therefore, someone who partially admits to a claim of "בית מלא" – a houseful of produce would not swear. Abaye says this only applies to a claim of "בית סתם" – an unspecified house, but if he claimed "בית זה" – this houseful of produce, then ידיעא טענתיה – his claim is known, i.e., the houseful is measurable, as well as the amount conceded by the נתבע (by measuring the produce currently in that house), and the נתבע must swear. Rava objects that the Mishnah contrasts the first case with one who claims the produce filled the house "עד הזיז" – up to the ceiling beam, and the נתבע responds that it was only full "עד החלון" – until the window. According to Abaye, the Mishnah should have taught that one even swears for a claim of "בית זה"!?

Rather, Rava says one only swears when both the claim and the admission can be precisely measured, like a claim of "עד הזיז" and an admission of "עד החלון". A Baraisa supports Rava’s opinion.

1. In a dispute about the value of a lost משכון, “the lender swears”

The next Mishnah discusses a lender who lost a משכון, and they disagree over its value, which would determine if a balance remains or not, or, if the משכון is worth more than the loan, the lender would pay the difference. Depending on the claim and counterclaim, there may be a shevuah of מודה במקצת. The Mishnah concludes: ומי נשבע – and who swears? מי שהפקדון אצלו – The one is possession of the deposit (i.e., משכון), שמא ישבע זה ויוציא הלה את הפקדון – because perhaps this borrower will swear to the משכון’s value (and may err in his assessment), and this lender will produce the deposit, and the borrower will become disqualified for עדות and shevuos.

This refers to where the borrower admitted the משכון was worth less than the loan, but claims it was more valuable than the lender claims (and is a מודה במקצת). The Gemara first explains that although the borrower should swear, the Rabbis removed the shevuah from him and placed it on the lender (to swear and collect). However, Rav Ashi explained that the lender swears שאינה ברשותו – that it is not in his possession, and the borrower swears כמה היה שוה – how much it was worth. Accordingly, the Mishnah merely means to teach that the lender swears first.

1. A משכון worth far less than the loan is lost: אבד קתא דמגלא אבדו אלפא זוזי

Shmuel taught that if one lent a thousand zuz, and the borrower gave a handle of a sickle (of little value) as a משכון, אבד קתא דמגלא אבד אלפא זוזי – if he lost the sickle handle, he lost a thousand zuz, because he cannot collect if he does not return the משכון. However, if the משכון was two sickles and he lost one, we do not consider each handle as against half the loan; rather, he merely deducts its actual value from the loan. Rav Nachman says he does lose half the loan in this case; however, if the משכון consisted of a sickle handle and a silver bar, the bar is not a משכון against half the loan. Since it is something collected for payment, the lender would only lose its actual value. The Nehardeans say that even if in this case, if the נסכא is lost, the lender loses half the loan.

The Mishnah, which clearly assumes that only the lost משכון’s value is deducted from the loan, is בדפריש – where [the lender] explicitly said that his responsibility for the משכון only according to its value.

Siman – Magazine. The lender who said he gave the borrower magazines that filled up to the ceiling beam of the house, and the borrower who said he only borrowed enough up until the window, didn’t notice that on top of the pile was “Lost Mashkon Magazine” covering the topic of the who swears regarding its value, which was next to a lost sickle handle mashkon that a lender lost which resulted in his not being able to collect the thousand zuz he had lent.