(Beraisa): Reuven borrowed money from a Nochri on Ribis. They calculated how much he owes (principal and Ribis combined), and wrote a document for this amount. The Nochri converted.

If he converted after they made the calculation, he collects it all;

If he converted before they made the calculation, he collects only the principal.

Similarly, if Reuven lent to a Nochri on Ribis, and they calculated how much he owes and wrote a document for this amount, and the Nochri converted:

If he converted after they made the calculation, he pays it all;

If he converted before they made the calculation, he pays only the principal.

R. Yosi says, if a Nochri borrowed, in either case he pays it all.

(Rava): The Halachah follows R. Yosi.

(Rava): R. Yosi's law is an enactment, lest people say that he converted in order to be exempt from the Ribis.

(Beraisa - R. Meir): If a document is for a loan on Ribis, we fine the lender, and he cannot use it to collect even principal;

Chachamim say, he can use it to collect principal, but not Ribis.

Question: What do they argue about?

Answer: R. Meir fines the permitted part due to the forbidden part. Chachamim do not fine the permitted part due to the forbidden part.

(Mishnah): Predated loan documents are invalid. Postdated documents are valid.

Question: Why are predated documents invalid?

Granted, they may not be used to collect from the date written, but they should be valid to collect from the date of the loan!

Answer #1 (Reish Lakish): Indeed, Chachamim say that they may be used to collect from the date of the loan. This Mishnah is R. Meir (who fines the permitted part due to the forbidden part).

Answer #2 (R. Yochanan): Chachamim admit in this case. It is a decree, lest he come to collect from the written date.

A case occurred in which Shimon gave his orchard to Reuven to be collateral for a loan. Reuven ate the Peros for three years, and threatened 'if you do not sell it to me, I will conceal the document that says that it was collateral, and I will claim that I bought it.' (Eating three years is a Chazakah, so he would be believed.) Shimon transferred ownership of the orchard to his son (a minor), then Shimon sold it to Reuven. Clearly, the sale to Reuven is invalid.

Question: Is the money Reuven paid like a loan with a document (the Achrayus entitles him to collect from Meshubadim)?

Or, is it like a Milveh Al Peh, which cannot be collected from Meshubadim?

Answer (Abaye): We learn this from R. Asi's law!

(R. Asi): If Levi admits that he authorized a document, Yehudah can use it against him, and Levi cannot demand that he validate it. (Shimon admits that Reuven paid for the orchard, like the document says. It is invalid to acquire the orchard, but it shows that Shimon owes him money!)

Rejection (Rava): The case of the orchard is different, for there was no Heter to write the document!

Question (Ravina): If so, why does R. Yochanan say that it is a decree not to collect from the latter date, lest he collect from the date written?

He should invalidate the document because there was no Heter to write it!

Answer (Mereimar): A predated document had a Heter to be written, i.e. with the date of the loan. There was no Heter to write the document of the orchard at all!

Question (Beraisa): Compensation for improvements: if Yehudah stole David's field and sold it to Levi, when David takes it back, Levi collects principal (what he paid) even from property that Yehudah sold, and improvements from Yehudah's Bnei Chorin.

We should say that the document should never have been written, so it is invalid!

Answer: One opinion holds that Yehudah does not want to be called a thief. The other opinion holds that he wants to act faithfully. Both agree that he will later buy the field from David to establish the document;

Here, Shimon wrote the document to prevent Reuven from keeping the field. Surely, he has no intent of fulfilling it!

(Mishnah): We may not contract to supply Peros for a set price until there is a set price (in the market);

Once there is a set price, even someone without Peros may contract, since other people have available Peros.

Reuven may contract (to supply the finished product) before there is a set price, if he already has a stack of grain, a container of grapes or olives, clay formed to make pots, or wood and stones that were put in the furnace to make plaster;

One may contract for manure all year round;

R. Yosi permits only if he has a pile. Chachamim permit (in any case)

He may contract at the cheap price;

R. Yehudah says, even if he did not contract at the cheap price, he can demand the cheap price or his money back.

(Gemara - R. Asi citing R. Yochanan): We may not contract according to the price in the market.

Question (R. Zeira): Did R. Yochanan say that even regarding a great market?

Answer (R. Asi): No, he said so only regarding a market of medium size cities, for the price is unstable.

Question: R. Zeira thought that perhaps R. Yochanan meant even a great market - if so, how does he establish the Mishnah?

Answer: The Mishnah discusses when people open their storehouses to sell and ships arrive with grain, for then the price is stable for a long time.

(Beraisa): We may not contract to supply Peros for a fixed price until there is a set price. Once there is a set price, even someone without Peros may contract, since other people have.

If new grain was selling for four (Sa'im for a Sela), and old (dry) grain for three, one may not contract (to buy new grain for four, since when he gets it, it will be dry. This is forbidden) until the prices equalize (at four).

If Leket (dropped grain that is left for poor people to take, which is inferior) was selling for four (Se'im for a Sela), and regular grain for three, one may not contract to buy regular grain for four until that becomes the price.

(Rav Nachman): One may contract with one selling Leket according to the price for Leket.

Question (Rava): Do you permit because the seller could borrow from another seller of Leket?

Also a regular seller could borrow from a seller of Leket!

Answer #1 (Rav Nachman): A regular seller would not borrow from a seller of Leket (it is below his dignity).

Answer #2 (Rav Nachman): One who buys from a regular seller pays for higher quality grain.

Version #1 - Rashi - (Rav Sheshes citing Rav Huna): We may not borrow (money, on condition that if he does not repay regarding a fixed date, he will give Peros) based on the market price (of today, which is cheaper).

Version #2 - Bahag - (Rav Sheshes citing Rav Huna): We may not borrow (a Se'ah on condition to return a Se'ah) even though there are Peros in the market. (One might have thought that since one can buy a Se'ah, it is as if the borrower has at home, in which case it is permitted.) (end of Version #2)

Question (Rav Yosef bar Chama): That contradicts another teaching of Rav Huna!

Question: May Talmidim borrow (Rashi - money; Bahag - Peros) in Tishrei and repay Peros in Teves (at the cheaper price of Teves)?

Answer (Rav Huna): Yes. The money could be used now to buy Peros elsewhere (Rashi - where it is cheap).

Answer: Originally, Rav Huna ruled that it was forbidden, until he heard that R. Shmuel bar Chiya permits it.