Rambam - 1 Chapter a Day

More precisely, the translation of this verb is “abuse.” We have chosen this translation with regard to business transactions, because as the Rambam states in this halachah, the prohibition against ona’ah applies even when a person unknowingly takes unfair advantage of a colleague. Thus, even when he is not consciously abusing his colleague, he is nevertheless transgressing. The understanding of the prohibition against ona’ah within the context of verbal abuse is developed in the latter part of Chapter 14.

Sefer HaMitzvot (Negative Commandment 250) and Sefer HaChinuch (Mitzvah 337) consider this to be one of the 613 mitzvot of the Torah.

By paying the amount that was over- [or under-] charged, or by nullifying the transaction, the person corrects the transgression. Since neither a transgression that can be corrected, nor a transgression that involves a financial penalty, is punishable by lashes, that punishment is not administered in this instance.

As the Rambam states in the following halachah, if the profit is less than one sixth of the value of the article, there is no requirement to return the money. Nevertheless, it is not sufficient to return an amount that will reduce the profit margin below one sixth; the entire profit must be returned.

The Maggid Mishneh objects to the Rambam’s ruling, explaining that although the margin of profit is less than one sixth when compared to the article’s value, it is more than one sixth when compared to the price the purchaser paid. Moreover, the unjust gain in this situation is a greater percentage of the article’s worth than if an article worth 60 were sold at 70.
Therefore, the Maggid Mishneh suggests the following principle: As long as the margin of gain is within a sixth, either from the standpoint of the seller or from that of the purchaser, we say that the ona’ah will be waived. On this basis, he maintains that the Rambam’s wording should be emended and changed to read “an article worth 70 dinarim for 60 and a p’rutah.” The Shulchan Aruch (Choshen Mishpat 227:3) quotes the example given by the Maggid Mishneh.
The Ramah (Choshen Mishpat 227:4) differs with the Maggid Mishneh’s premise and maintains that ona’ah is determined always with regard to the value of the object sold and not the amount of money the person paid. For it is in the appreciation of the article’s value that an error can be made.

The Rambam’s wording leads to the inference that taking any amount of unfair gain is forbidden. Nevertheless, since a person is wont to waive this amount in business transactions, the person who took the unfair gain is not required to return it. Note, however, Hilchot Geneivah 7:5, which states that as long as a coin is worth 5/6 of its value, it is permitted to use it for a business transaction, for people are wont to forgo up to a sixth of the value.
The Tur (Choshen Mishpat 227) states:
Since the Torah states: “Do not take unfair gain,”... if the seller or the purchaser is aware that he is taking unfair gain... it is forbidden.... Or perhaps since it is an ordinary business practice [to mark up one’s merchandise],... this is therefore not called ona’ah at all.
See also the Shulehan Arueh (loc. cit.:6).

The Maggid Mishneh draws attention to Chapter 27, Halachah 5, which states that if it is plainly obvious that there is unfair gain involved - e.g., a person sold an article for double its worth - the laws of ona’ah do not apply. Instead, we assume that the purchaser was giving the seller a present.

The Tur (loc. cit.) and Sefer Me’irat Einayim 227:6 emphasize that the purchaser may not demand: “Let the purchase stand; just return the unfair gain to me.” Instead, he must either keep the merchandise at the price he paid, or return it to the seller.

The rationale is that since he was the one who wronged his colleague, he is not given any prerogative with regard to the nullification of the transaction. The Tur and the Ramah (Choshen Mishpat 227:4) differ and maintain that since the transaction is not binding, even the one who wronged his colleague can bring about its nullification. (See also Halachah 13 and notes.)

It would appear that according to the Rambam, as long as the unfair gain exceeds a p’rutah, it must be returned. The Rambam’s opinion [quoted by the Shulehan Arueh (Choshen Mishpat 227:5)] is thus an intermediate view between two opinions quoted by the Tur: one (also cited by the Ramah), which requires even a p’rutah of unfair gain to be returned, and another (cited by Sefer Me’irat Einayim 227:12), which maintains that unless the ona’ah is a m’ah, the smallest silver coin, it is not considered of consequence and need not be returned.
[Sefer Me’irat Einayim also maintains that the Rambam subscribes to the view he explains. Significantly, it is advanced by Rabbenu Yitzchak: Alfasi, the teacher of the Ri Migash, the Rambam’s own teacher.]

Kiryat Sefer distinguishes between robbery, where a p’rutah must be returned, and the law at hand as follows. In robbery, the person did not receive anything. In this instance, a transaction was involved, and he received something for his money or property. Hence, since the unfair gain was only a p’rutah, it is not of consequence.

Perhaps we should have used the word “opportunity.” For as the Shulchan Aruch (Choshen Mishpat 227:7) writes, if he is prevented from appraising the article by forces beyond his control, he has the right to protest afterwards.

Who can honestly appraise the article for him.

I.e., a relative knowledgeable in this field.

Although the Rambam is obviously pointing to an exaggerated difference in value, based on Chapter 27, Halachah 5, his wording in this halachah is not precise.

Since he did not take the opportunity to inquire whether or not his transaction was worth the price he paid for it, we assume that he desired it and was willing to purchase it at any cost. Thus, he forfeits his right to protest.

When the unfair gain is an even sixth.

When the unfair gain is more than a sixth.

Since there is no way we can guarantee that he will see a similar article in a given time, he is always given the opportunity to retract.

For he will always be able to see if he received a fair price or not.

The halachic principle governing this and the previous rulings is that once a person has waived a particular right, he cannot reclaim it.

One might think that since a merchant is knowledgeable with regard to prices, that he was aware of the true value of the article. Thus, if he purchased it or sold it for considerably more or less than its value, he was giving a present to the other party. The Rambam states that this is not the case and that there is also the possibility that he will err.

Sefer Me’irat Einayim 227:26 explains that since the Torah mentions ona’ah with regard to a sale, one might think that these laws do not apply with regard to the exchange of coins, for such a transaction is not regarded as a sale. Therefore, the Rambam emphasizes that the laws do apply.

I.e., according to the Rambam, the measure of one sixth applies with regard to the exchange of coins as well. The Maggid Mishneh, the Tur and the Ramah (Choshen Mishpat 227:15) differ and maintain that with regard to coins the measure of ona’ah is one twelfth. When there is any greater gain, the transaction is nullified. If there is a lesser gain, it is allowed to stand without change.
Sefer Me’irat Einayim explains that a smaller figure is mentioned with regard to coins, because people are very careful with regard to their value and expect to be given a fair exchange.

At that time, the value of coins was determined by their weight, not by their face value. If a coin was the approximate size, but not the proper weight, the laws of ona’ah applied.

If, however, the sela’im are being exchanged by weight, the transaction would be nullified in such an instance, as reflected in Chapter 15 [Maggid Mishneh; Shulchan Aruch (Choshen Mishpat 227:16)].

In Halachot 5-7, a standard amount of time was allocated in which the worth of an article was to be evaluated, or else the person is considered to have waived his right to protest. A similar concept applies with regard to coins. The determination of that amount of time is the subject of this halachah.

For villagers often come to the cities before the end of the week to purchase their Sabbath needs, and on that trip they could have the coin evaluated.

The Rambam was speaking before the age of the printing press, when books (more precisely, scrolls) were extremely valuable articles, whose worth could be appraised only by experts.

Since there was no way that the purchaser could have the article appraised, the passage of time is of no consequence.

As the one that was given.

The Maggid Mishneh interprets the Rambam’s words as meaning that even if a person who received a coin of improper weight did not return it in the time allotted in the previous halachah, he may still return it at a later time if it will not be accepted as currency. If it will be accepted, even with difficulty, the person who gave it is not obligated to take it back.
The rationale for the Rambam’s ruling is that if the person cannot use the coin he received, this is not merely a case of taking unfair profit, but rather of giving an article with a defect.

I.e., the time mentioned in the previous halachah.

The Rambam’s ruling is based on his understanding of Bava Metzia 52b. The Tur and the Shulchan Aruch (Choshen Mishpat 227:17) offer a different interpretation, explaining that even if the coin is not acceptable as currency, the one who gave it is not obligated to accept it after the time period mentioned in the previous halachah.

Halachah 4.

Even the opinions mentioned by the Ramah (Choshen Mishpat 227:4) that ordinarily allow the seller to retract do not give him that option in this situation.

An unfair gain sufficient to nullify the transaction.

As stated in Halachot 1 and 2.
Thus, in addition to the profit the purchaser gains from the increase in the value of the object, he also gains another zuz from the seller.

I.e., in addition to the loss he suffered because of the article’s decrease in value, he must pay another zuz from his pocket.