Rambam - 1 Chapter a Day

I.e., this law serves as a contrast to the principles stated in Halachot 8 and 12 of the previous chapter. The rationale for the difference is that with regard to rent and wages, payment is not required until the term of rental or the work is completed. With regard to a sale, by contrast, the purchaser is obligated to pay for the purchase upon completion of the transaction. Hence, it is obvious that the increase is being granted because of the delay in payment.

And this is its fair market value.

Such arrangements were common in the Talmudic period and are still common today. For the immediate availability of cash is worth money.
The commentaries to the Shulchan Aruch (Yoreh De’ah 173:1) states that such a transaction is forbidden even if at the time the payment is due, the value of the article would have appreciated to the higher price.

It is not considered to be interest forbidden by Scriptural Law, because the basis of the transaction is a sale, and not a loan [Beit Yosef (Yoreh De'ah 173)].

I.e., the purchaser did not pay immediately. Hence, the seller demanded the larger sum. The purchaser cannot be compelled to pay this amount, because “the shade of interest” is not expropriated by the court (Chapter 6, Halachah 1).

The Maggid Mishneh cites the Rashba, who maintains that if the article does not have an established market price, it is permitted to make such an offer. The Shulchan Aruch (loc. cit.) quotes this view, adding the proviso that the seller cannot explicitly say: “If you pay now you can buy it for this price, but if you pay later you must pay more.” The Shulchan Aruch, however, also quotes another view, that states that even if an explicit statement is not made, if it is obvious that he is charging more because he is accepting later payment, it is forbidden.

Provided that the seller is willing to take the article back. It is the seller’s prerogative, not the purchaser’s (Lechem Mishneh).

This principle does not apply with regard to landed property. For with regard to landed property, the laws of ona’ah (taking unfair advantage of a purchaser or seller) do not apply (Hilchot Mechirah 13:8). Moreover, every parcel of land is unique, and one cannot say what the market value of any particular parcel would be (Maggid Mishneh)

This law applies even if the seller did not explicitly say that the purchaser could pay a lower amount if he paid immediately.

The Beit Yosef (Yoreh De’ah 173) states that the original transaction must be completed before this stipulation is made.

Grapes are harvested in the summer, and wine made in the early fall. Thus, wine is plentiful in the fall, and hence inexpensive. In the summer, by contrast, supplies of the previous year’s wine are already scarce, and the new wine is not yet available. Hence, the price is higher. Thus, it is legitimate for a wholesaler to ask for a higher price in the summer, because the wine is worth more. Nevertheless, to prevent any question of interest, the seller must accept responsibility for losses caused by outside factors.
If, for some reason, the purchaser desires to use the wine before the summer, he must pay the entire fee [Beit Yosef (Yoreh De’ah 173)].

In such a situation, since the wholesaler accepts a large portion of the risk, he is entitled to a share of the profits.

There are commentaries that suggest that it was due to a printer’s error that this sentence was included in this clause, and that it should be included in the conclusion of the following clause. For otherwise, a) the wholesaler is taking too much responsibility; b) the second clause would be obvious. The standard printed text of the Shulchan Aruch (Yoreh De’ah 173:14) quotes the printed version and the Siftei Cohen 173:29 suggests making this correction.

Since the wholesaler accepts responsibility for the sale of the article, he does not have to accept responsibility for its loss. He is a partner in the sale, and there is no question of interest involved.

I.e., when the seller is anxious to sell the article, he will be willing to accept a slightly lesser price. Conversely, when the purchaser is anxious to buy the article, he will be willing to pay slightly more.

I.e., although the seller is taking the initiative, receiving the higher price is not considered to be taking interest, because there are circumstances where the purchaser would pay that price immediately.

And pay the funds immediately.

There is a certain element of risk involved, for the produce could become ruined. Nevertheless, once the produce is already in a developed state, the likelihood of that happening is small (in contrast to the second clause). Hence, it is not considered significant.
The commentaries note the contrast to Chapter 9, Halachah 10, and explain that in the latter instance, there is virtually no work involved; garden vegetables grow as if on their own accord. Caring for fruit in an orchard, by contrast, requires much more work. Hence, having the seller perform that work without receiving recompense resembles interest.

I.e., the purchaser receives a greater value because he waits until the later date for delivery of the produce. Although the increase in the value of the produce comes naturally, since it is in preliminary stages of growth, it also needs care and tending to. It is considered interest for the seller to perform those tasks. When, however, next to no work is necessary for produce to grow - e.g., squash - these restrictions do not apply [Shulchan Aruch (Yoreh De’ah 173:8)].
The Kessef Mishneh suggests a halachic mechanism to prevent the question of interest from arising. The purchaser can buy the trees of the orchard with regard to their fruit. In this manner, the produce itself is not the object of the sale. Hence, its increase in value is not significant.

And he accepts responsibility for it.

Hence, the original owner is receiving an additional amount, not only for delaying payment, but for accepting the risk that the animal will become weak or die.
The Ra’avad differs with the Rambam’s interpretation, but does not explain his point of contention. The Maggid Mishneh justifies the Rambam’s perspective, and it is quoted by the Shulchan Aruch (Yoreh De’ah 173:10) without any objections from the commentaries.

I.e., and receiving ownership at the time of the purchase.

Therefore, the branches are considered to have increased in value in his possession.

Because he is not receiving anything at the time he makes payment. Therefore, the money he gives is comparable to a loan that will not be repaid until the vines are pruned.

I.e., instead of receiving payment in cash, the watchmen are paid in produce from the field. They are, however, given a bonus, and the amount of produce they are given is calculated according to a lower price than the going market value.

E. g., in threshing and/or winnowing the grain.

A worker's wages are not due until he completes the task for which he is hired. Therefore, in this situation, the term of the workers' employment must continue until they collect their wages. Thus, there will be no question of interest involved, because their wages will be paid at the time their wages are due. Although the employer will be selling the grain lower than its market value, he is entitled to do so.

I.e., if they complete their task beforehand, their wages will fall due at that time. During the time between the completion of their tasks and their collection of the grain, the money owed them for their work will be considered as having been loaned by them to the employer.

A kor is equivalent to 30 se’ah.

This is considered to be extending the lease on the field for a higher rent, not as giving the owner an extra two se’ah for postponing the day of payment (Maggid Mishneh).

Thus, his gift was no more than a present and is not considered as interest.

Since there is no stipulation requiring him to pay an extra amount, there is no question of interest involved. As stated in Chapter 4, Halachah 10, one may give a present to a person from whom one received a loan. Moreover, in this instance there is added room for leniency, because the basis of the transaction was a sale, and not a loan.

In contrast to the second clause, this clause is speaking about even a specific barrel of wine.

Since payment is made at the outset and the delivery is not until later, there is a certain resemblance to a loan at interest. Nevertheless, as the Rambam continues to explain, it should be seen as an investment by the purchaser, in which there is a possibility of loss.

As stated in Chapter 5, Halachah 8, it is forbidden for a person to enter into a transaction where an investment is made and there is little possibility of loss, but a possibility of gain, for this resembles a loan at interest. Nevertheless, since there is the possibility that the value of the wine will depreciate, this transaction is not placed in that category. If, however, the purchaser does not accept this possibility, the transaction is forbidden [Shulchan Aruch (Yoreh De’ah 173:13)].

That was the terms of the original agreement.

So it was as if they were never really sold at the outset. It is like a transaction conducted under false premises, for the purchaser would not have desired to buy the jugs containing the vinegar.

Since the renter accepts responsibility for the ship, there is room to consider the relationship as a loan. For if it is damaged, the person who rents it becomes responsible for it from the time he took possession. In such a scenario, the fee that he pays could be considered comparable to interest paid on the loan. We do not follow this perspective. Instead, we consider this an ordinary rental agreement; the fact that the renter takes responsibility for the value of the article even when he is not obligated to do so is not significant. See Halachah 2:9 for related concepts.

Here also, the arrangement is considered to be a rental and not a loan at interest.

It is, however, permitted to enter into such a relationship with a gentile, either as an investor or as the shepherd, because there is no prohibition against receiving interest from or paying interest to such a person (Chapter 5, Halachah 2).

Although the Mishnah (Bava Metzia 70b) uses the term “interest,” and not “the shade of interest,” the Rambam’s interpretation is accepted by all, for the basis of the relationship is an investment, and not a loan.

Literally, "iron sheep." This term was used because the shepherd accepts responsibility for the sheep, so that their value - like iron - will remain intact, without ruin. See also Hilchot Ishut 16:1, which uses a similar term.

In other words, the owner of the sheep invests the capital - e.g., the sheep - while the shepherd invests the effort in caring for them, and they split the profits.

Investments of such nature are forbidden. Instead, when a person invests money, there must be a significant element of risk involved. Otherwise, the arrangement resembles a loan at interest, as stated in Chapter 5, Halachah 8.

I.e., the shepherd is not held responsible for the loss. The Rambam appears to be saying that the owner must undertake the risk both of the sheep's depreciation and of their being seized by predators. If he accepts only one of these risks, the arrangement is forbidden.
The above reflects the interpretation advanced by the Beit Yosef (Yoreh De’ah 177). The Yemenite manuscripts of the Mishneh Torah, however, read: “accepts the condition that should the value of the sheep increase or decrease, they are considered within his domain, or should they be seized by predators, they are considered within his domain.” According to this version, the owner is required to accept one, but not both, of the risks.

I.e., a person has a cow that he seeks to hire out to a recipient. That person establishes a price for the cow to be paid in the event of its death, and a fee to be paid monthly for its hire.

Even if at the time of its death it was not worth that amount, since it was worth this amount at the time it was rented, the renter is obligated to pay this amount. The Ramban differs, and maintains that the renter can be required to pay only the value of the cow at the time of its death. (Maggid Mishneh). The Shulchan Aruch (Yoreh De’ah 176:4) follows the Rambam’s view, while the Ramah cites the other opinion.

Since the person who rents the cow for labor accepts responsibility for it, there is room to say that the transaction is comparable to a loan, and the fee comparable to interest. This, however, is not the conclusion accepted by our Sages. They follow the logic mentioned in the notes on Halachah 11, considering this to be an ordinary rental with a stipulation attached.
Indeed, the commentaries raise questions: Bava Metzia 69b is the source for both this halachah and Halachah 11. Moreover, it considers Halachah 11 as logically contingent on this halachah. Why does the Rambam interrupt the two with another concept? And why does he mention Halachah 11 first? See, however, the conclusion of the following note.

I.e., he becomes responsible for the value of the animal only if it dies. If he returns the animal alive, he is not responsible if its value depreciated because of the work and when it is returned, it is not worth 30 dinarim. Since there is a certain amount of risk involved, our Sages did not consider this comparable to "the iron sheep" mentioned in the previous halachah and permitted the arrangement.

The owner of the chicken is not responsible for the eggs, but must perform certain tasks to protect them [Maggid Mishneh in the name of Rashi (Bava Metzia 68b)].

The arrangement is not considered a loan, and the fee (the chicks) as interest. Instead, this is also considered to be a rental (Kessef Mishneh).

I.e., as interest forbidden by Scriptural Law, which can be expropriated through legal process.

I.e., an article that can no longer be singled out - e.g., produce - or was lost or destroyed. Otherwise, the article itself should be returned, as the Rambam proceeds to state.

I.e., the value of the article, not the amount that he owed. Although it was given as interest and thus a prohibition is involved, its full value must be paid.

Similar laws apply to any article that can be identified.

Bava Metzia 65a states the reason for this: So that people do not say: “The cloak he is wearing was acquired through taking interest.”

Although the Rambam spoke of movable property when stating the law regarding taking more than the amount owed as interest, and spoke of landed property when stating the law regarding taking less than the amount owed as interest, similar principles apply if the situations are reversed (Kessef Mishneh). Indeed, when citing this law in his Shulchan Aruch (Yoreh De’ah 161:10), Rav Yosef Karo speaks of renting an article in lieu of the interest.