Gemara: Aren't robbery and personal injury monetary matters? [Obviously, they are, so why were they listed explicitly in the mishna?]
R. Abbahu said: [The mishna] teaches what they (monetary matters) are. [According to R. Abbahu, "monetary matters" is a general heading, of which the following phrases specify sub-categories.] What _are_ monetary cases? Robbery and personal injury, but not admissions and loans. [Rashi: "Admissions" refers to cases in which the lender has witnesses that the borrower admitted borrowing the money. Loans are cases in which the lender has witnesses who were present when the loan took place.]
And both phrases are necessary. For if the mishna taught (only) "monetary laws," I might have said that even admissions and loans (require courts of three); therefore, the mishna specifies "robbery and personal injury" (to exclude admissions and loans from the requirement).
And if the mishna (only) taught "robbery and personal injury" and did not teach "monetary matters," I would have believed that this applies even to admissions and loans, and that the only reason it specified robbery and personal injury is because the basic biblical source for three judges is with respect to robbery and personal injury.
[The gemara will now attempt to establish R. Abbahu's opinion by biblical exegesis.]
Robbery [requires three judges], as it is written (Ex 22:7) "If the thief be not found, then the master of the house shall come near unto God." [Rabbinical exegesis interprets "God" to refer to judges. Rashi explains that the term "God" appears twice in the next verse, for a total of three times, indicating that three judges are required for robbery.]
Personal injury -- what difference does it make whether one injures a person or property? [If the requirement of three judges for cases of property loss (Ex 22:7) can be extended by analogy to cases of personal injury then it must be regarded merely as an illustration of a general rule, which would apply to admissions and loans, which involve "property loss" as well.]
Therefore, the mishna states "What are monetary cases? -- robbery and personal injury, but not admissions and loans. And from what (are admissions and loans excluded)? If you will say that they do not require three judges, didn't R. Abbahu say that two judges who ruled in monetary cases, everyone agrees that their ruling is not valid? [It thus can't be that R. Abbahu holds that two judges can rule in cases of admissions and loans, so how can he say that three are not required?]
Instead (the mishna means that for admissions and loans) we do not require expert judges [Rashi: ordained judges whose status was granted by the Nasi or Patriarch].
[In the analysis of R. Abbahu's opinion that the mishnah mandates a court of three expert judges for cases of robbery and personal injury, use is made of an exegetic device known as "interweaving of sections" (eruv parshiot). In it, clauses from one biblical section (i.e. verse or group of verses dealing with a certain topic are taken over, for interpretative purposes, to another section.]
[The group of verses Ex. 22:6-8, applies to an unpaid custodian who misappropriates a deposit. This is regarded as equivalent to robbery, so the three references to God in this section is the basis of the rule that robbery must be tried in a three-man court. On (Bava Kama 107a) the clause "...whereof one sayeth `This is it'..." in Ex. 22:8 is associated with Exodus 22:24, which deals with monetary loans, and interpreted exegetically to mean that a borrower who admits partial liability {e.g., I borrowed 10 shekels, not 20} must take an oath. The "interweaving" of these two verses implies that the rules applying to borrowers are equivalent in some way to rules applying to misappropriating custodians.]
What does he [R. Abbahu] hold? If he holds (that there is) "interweaving of verses", then expert judges should be required here (in the case of loans) too. And if he does not accept "interweaving of verses", [so that these verses do not apply to loans at all], why do we need three judges (of any kind for loans)?
[Either way, the attempt to base R. Abbahu's distinction, between robbery and personal injury on the one hand and admissions and loans on the other, on biblical exegesis is unsuccessful.]
[The gemara concludes:] Actually, he (R. Abbahu) _does_ accept "interweaving of sections", and expert judges _should_ be required. But we do not require expert judges [for admissions and loans] because of (the words of) R. Hanina. As R. Hanina said: According to the Torah, monetary cases and capital cases both require inquiry and investigation [which only expert-judges can carry out], as it says (Lev 24:22) "Ye shall have one manner of law." [Lev 24:21 refers to a person who killed an animal or another person, suggesting that one manner of law apply to both capital and monetary cases.]
But why don't monetary cases require inquiry and investigation? In order not to lock the door before borrowers. [Rashi: If the strict rules of evidence were to apply to loans, even a minor inconsistency could disqualify testimony, and lenders might feel that they would be unlikely to successfully sue for loan repayment ... and stop making loans.]
If so, [if even non-expert judges can rule in cases of loans], if they erred, they won't pay [i.e., to reimburse the lender for the loss that they caused him through judicial error?) [The gemara will later rule that an expert judge who makes a judicial error is not liable for payment, but an non-expert judge _is_ liable.]
Then you would certainly be locking the door before borrowers. [Non-expert judges, who are not authorized to carry out the full judicial process (inquiry and investigation), would be more likely to make erroneous judgements. The lender would hesitate to make the loan if he would have to litigate before such a court in case of non-payment, unless the judges were liable to pay for any judicial errors they might make.]
[We end on the fifth line of San 3a.]