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He Sold His Birthright to Yaakov: Sale of ‘Futures’ in Jewish Law


Parashas Toldos opens with one of the most renowned transactions of all time: The sale of the birthright from Eisav to Yaakov.

Commentaries write at length about this sale, with discussions dividing into two main topics: One is the content of the sale—what was sold, what was the essence of the sale and what is its inner meaning? The other is the halachic meaning: Was the sale legally binding, and is it in fact possible to sell a birthright?

The two topics are deeply related. According to certain commentaries, Yaakov bought the right to the priesthood, which was initially given to the firstborns (see Rashi, Bereishis 25:31; see also Chizkuni, and other commentaries). Some explain that Yaakov bought the honor that attends the birthright (see Ibn Ezra, second interpretation; see also Chizkuni, Rabbeinu Bachya, and others).

Based on these interpretations, there is a halachic difficulty that calls the validity of the sale into question: According to  halacha, it is not possible to sell something that is not concrete or tangible (ein bo mamash; see Rambam, Mechirah 22:13).

However, the majority of commentaries write that the object of the sale was Eisav’s future inheritance from Yitzchak, which Eisav (who by dint of the birthright was slated to receive a greater portion) sold to Yaakov (see Ramban, Bereishis 25:31; Ibn Ezra (first interpretation); Rashbam; Chizkuni (third interpretation), among others). This interpretation, too, raises a clear halachic problem: one cannot sell a “davar shelo ba la-olam,” an entity that does not yet exist.

This question has far-reaching consequences for the modern world. A great many transactions today involve items that are not yet in the seller’s possession. This is true of futures contracts, of real estate sales for property yet to be built, of receivables and for large wholesale transactions where the seller has yet to take possession of what he is selling. Why it is not possible to sell or buy a future entity? How can this problem be overcome? And how, indeed, did Yaakov purchase the birthright?

We will discuss these questions, among others, below.

Selling a Future Entity

The basic halachic principle is that one cannot sell an entity that has not yet come into existence, or that has not yet come into the possession of the seller. Examples are sales of fruit or grain that have not yet grown, water that is due to fill a pool, tort damage payments for damage yet to be done, the sale of a field not yet bought (by the seller), and so on.

This matter is the subject of a dispute recorded in the Mishnah (Kidushin 61 A). According to Rabbi Meir, a person can make this type of transaction, whereas the Sages (Chachamim) maintain that this cannot be done. The Gemara (Bava Basra 79b, and other places) explains that even according to Rabbi Meir, one can only sell a future entity that is expected, in the normal course of events, to come into the world.

For instance, the future fruit of a tree, which usually appears annually, can be sold according to Rabbi Meir, but not according to the Sages. This is not the case for damage payments, which cannot be predicted.

The halacha follows the opinion of the Sages, as the Rambam and Shulchan Aruch (211:1) rule. So it appears that any sale of a future entity will have no validity in Jewish law.

Exceptions: Burial Requirements

The Tosefta (Nedarim 6:7; Bava Metzia 4:10) expresses this halacha in the context of inheritance: “‘I sell you what I will inherit from my father’—this has no legal validity.”

The Tosefta proceeds to stipulate an exception: If a person sells the inheritance he will receive later that day from his father’s estate, the transaction is valid.  Likewise, if a person sells the animals he will hunt that day, the sale is valid.

The Gemara (Bava Metzia 16a) explains that two exceptions to the rule of future sales are implied by the Tosefta. One relates to laws of inheritance: Although one cannot, in general, sell a future inheritance, one can do so when it is done to pay for the father’s burial. This is a rabbinic enactment (as Rashi notes) made to ensure that the son will have the wherewithal to pay for the burial costs of his father.

The Beis Yosef (Choshen Mishpat 211) and Biur HaGra (211:2) underscore that this halacha is not limited to a father as the result of the mitzvah of honoring one’s parents, but rather applies to any inheritor to whom the obligation of burial applies.

The second exception refers to an immediate financial need of somebody who is poor. When a sale is made for immediate needs, then the sale is valid: “‘That which my net shall catch today.’ The sale is valid, to provide for his livelihood.”

Halachic Ruling

These two exceptions are ruled in halacha. In the matter of inheritance the Rambam (Mechira 22:6) rules that when a person is close to death and wishes to sell part of his estate to ensure the availability of funds for his burial, then the sale is valid. However, this is limited to sales for the purpose of honoring the deceased:

“When a person was on his deathbed and the heir desired to sell some of the dying person’s property to spend the money for the sake of the burial, our Sages ordained that if the heir says: ‘What I will inherit from my father today is sold to you,’ the sale is binding. The rationale is that since the son is poor, if he is forced to wait until his father dies to sell the property, the corpse will remain unburied and be disgraced.”

The Rema adds (Choshen Mishpat 211) that we are not particular about the precise sum that is required for the burial, and even if the sum is exceeded, the sale is valid.

The second exception is also ruled by the Rambam and the Shulchan Aruch:

“Similarly, provisions were made for a poor fisherman who has nothing to eat. If he says: ‘What my net brings in today from the sea is sold to you,’ the sale is binding. This was ordained to provide for his livelihood.”

Note that there is also a third exception: a specific item property. This exception is based on the ruling of Rabbeinu Tam (see Tosafos, Kesubos 91a), and is ruled by the Rema: “Some say that the principle applies only in general. But if a person says, ‘This field that I shall inherit from my father is sold to you,’ the sale is valid.”

Explaining the Sale of the Birthright

Based on the aforesaid principles, some commentaries explain the sale of the birthright to Yaakov as meeting the valid exceptions. The Or Ha-Chaim Ha-Kadosh explains that this is the reason why Yaakov, in his demand for the sale of the birthright, mentions the word “kayom,” today. The sale “today” of the birthright was valid because Eisav was “tired,” and needed his brother’s soup to save his life.

He adds that although Yitzchak did not die on the same day, the sale is nonetheless binding, for it depends not on the event taking place on the same day but rather to the gains of a single day rather than long-term gains. The Tur, in his commentary on the Torah, explains it similarly, though he adds that while Yaakov only asked for the inheritance of “that day,” Eisav agreed to a sale forever.

Another explanation for the validity of the sale relies on the oath that Yaakov demanded of Eisav. The Tur cites his father, the Rosh, who said that the oath renders the sale valid, in addition to the  obligation upon the seller to keep his oath.

This opinion is based on the reason one cannot contract a future sale. One reason (see Kovetz Shiurim, Bava Basra no. 276) is a lack of gemirus daas. We assume that generally the buyer and seller cannot reach a binding agreement concerning something intangible. However, if the seller takes an oath to sell, this religious obligation will suffice to create a mutual agreement and reliance between the parties.

The Rivash (328; see also no. 335) rejects this approach, and writes that an oath cannot give validity to a sale. Concerning the proof adduced from the sale of the birthright, he explains that this cannot be considered a proof because it is possible that before the Torah was given, future transactions were binding, and only after the giving of the Torah did they become invalid.

The oath, according to the Rivash, was only an extra element, which Yaakov demanded because he knew that his brother could not be trusted.

The Situmta as Future Transaction

A fourth possibility for understanding the validity of the transaction is based on a principle noted by the Tashbatz in the name of Maharam (Tashbatz Katan, no. 398). The question that the Tashbatz addresses is especially pertinent to modern financial transactions: What is the halacha in cases in which selling futures is the common custom, part of the fiscal everyday reality?

Assuming that the flaw in a futures sale is the lack of full mental agreement between the sides, it can be argued that where this type of sale is common, this is no longer an issue. This would fall under the category of situmta, which means a transaction based on custom (see Shulchan Aruch 201, Ketzos Hachoshen and Pischei Teshuva on this matter).

The Tashbatz writes, indeed, that where future sales are common custom, they have halachic validity. This implies that where a change in fiscal custom brings about a new situation, whereby it is common to sell futures, this will no longer have the flaw of davar she-lo ba la-olam.

Along similar lines, the Rashbam writes that the sale of the birthright was binding because it was enacted with a situmta, a transaction based on the custom. He bases this on the assumption that the eating of the bread and soup was a customary way of validating the transaction (see also Radak; Chizkuni; Shut Maharam no. 730).

An interesting case in point noted by the Tashbatz, concerning which authorities discuss the validity of the situmta for a future transaction, is the case of somebody who bought the right to circumcise his friend’s unborn child. Rabbi Yechiel of Paris ruled that the transaction was not binding because the child was not yet alive at the time of the sale.

It is possible that Rabbi Yechiel maintained that the issue in making future transactions is not merely the lack of full agreement between the parties, but a deeper flaw whereby it is impossible to make a transaction for an item that does not exist (see Kovetz Shiurim, cited above).

Maharam of Rotenberg, however, disputed that ruling, explaining that where it is customary to accept the transaction, the force of the custom will be binding even in Torah law.


We have seen that although a futures transaction is not generally valid in halacha, there are a number of exceptions that the Sages made to the rule, for cases in which there is an urgent need to consummate the sale. In addition, it is possible that where it is customary to uphold such sales, the force of custom will be binding even according to halacha. This, of course, is significant in modern times, when future sales are an accepted part of day-to-day commerce.

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