1. The Gemara discusses a case of two people who deposited money by a third person, and each claims to have deposited the higher amount.
2. Tana Kama: Each person takes 100 Zuz, and the rest is put aside until Eliyahu ha'Navi arrives.
3. Rebbi Yosi: Neither of them receives any of the money that they deposited.
4. If a person lends money with interest, he does not receive even the principle in return.
5. The Chachamim argue that he does collect the principle.
A BIT MORE
1. For example, Reuven and Shimon each deposited money with Levi at the same time. Reuven claims that he deposited 200 Zuz and Shimon deposited 100 Zuz. Shimon claims that he was the one who deposited the 200 Zuz. Levi has no idea who deposited which amount of money.
2. It is clear that each one deserves at least 100, since that is the minimum that each person definitely deposited. The remaining 100 is put aside until Eliyahu ha'Navi arrives to tell us who was telling the truth.
3. This is in order to deter a person who deposits 100 from claiming that he deposited 200. According to the Tana Kama, he has nothing to lose if he lies, since he will still get his 100 whether or not his claim is accepted.
4. Rebbi Meir says that since a Jew is not allowed to lend money to another Jew with interest, he is fined so that he cannot even collect the principle of the loan.
5. This is because lending the principle is a permitted act.