Rambam - 1 Chapter a Day

Since the article does not yet exist, ownership over it cannot be transferred.

See the explanation of this convention in Hilclwt ‘Zechiyah UMatanah, Chapters 8-12.

This ruling applies even if the animal is already pregnant [Shulchan Aruch (Choshen Mishpat 209:4)].

I.e., this indicates that the agreement does not automatically take effect once the produce comes into existence.

This ruling is somewhat difficult to understand. For according to the previous and following clauses of this halachah, the agreement is not binding at all. As such, the seller should seemingly be able to retract and expropriate the produce from the purchaser if he desires.
The commentaries explain that once the purchaser has taken possession of them, it is as if the seller has formally waived his rights over them. The protests that he issues later are considered to have been issued after the fact. (See D’rishah, Choshen Mishpat 209.)

Because the agreement was never binding.

The Rambam is referring to a convention frequently employed by farmers who desire to sell their crops even though they have yet not harvested them. If, for example, a market price for grain has already been established, a farmer may sell grain that he intends to harvest, so that he will have ready cash and deliver the produce later. Even if the price of the produce rises afterwards, this is permitted and is not considered to be involving interest, because the purchaser could buy the produce in the market place at that time. If, however, the produce is not available on the market and a price has not been established, it is forbidden to pre-purchase produce from a farmer. Doing so is prohibited as part of the Rabbinic prohibitions against interest. See Hilchot Malveh V’Loveh 9:1.

I.e., it is considered to be a sale that was completed, but the produce was· not delivered, in which instance the adjuration mi shepara is in place.
Although, as the Rambam states in Halachah 5, a person cannot sell an entity that is not in his possession, this situation is considered to be an exception, because the produce is easily available in the market place (Kessef Mishneh).

A farmer who is in dire need of funds might be willing to make such an agreement even if it involves offering the purchaser a considerable profit.

Generally, a farmer may not sell produce until the harvest-time, when the produce is already fully ripened. This instance describes a preliminary stage, where the produce is far from ready to be harvested. Nevertheless, an exception is made and the produce is allowed to be old if the conditions mentioned by the Rambam are met.
The difficulty with selling the produce in a preliminary stage is that we question whether the buyer or the seller will consider Ute transaction as having been in fact completed. When Ute produce is available in the market place, even when the seller does not himself own any produce, the sale is taken seriously, because the produce is accessible and its price has already been fixed. When, however, the produce is in a preliminary stage, it is possible that the purchaser will consider buying it from others, and that the seller, knowing that possibility, will also not take the sale seriously.

In which instance, both parties take the sale seriously, because it is associated with an article that actually exists.

In which instance, the issue of whether the sale is to be considered seriously has clearly been addressed.

Bava Metzia 63b relates that this was in fact a frequent practice. Realizing that he would receive a low price, a wholesaler would buy wheat from several farmers, waiting to see whose fields would produce the best crops. Afterwards, he would renege from certain of these sales.

The rationale is that for the purchaser, it is as if the article does not exist. It is not in his power to sell it.

The Tur and the Ramah (Choshen Mishpat 211:1) agree with the Rambam’s ruling when the seller states “a field that I will inherit.” If, however, he states “this field that I will inherit,” these authorities maintain that the sale is binding. For since he will ultimately inherit the field, and he specifies the article explicitly, the sale is binding.
(Kin’at Eliyahu explains that this ruling reflects a difference in the appreciation of the underlying rationale for this concept. According to the Rambam, the difficulty is that since the person does not own the field, he cannot sell it. According to the Tur, the difficulty is that since the person does not own the field, neither he nor the purchaser will take the sale seriously. Therefore, when there is reason - as in this instance - to say that they will take the sale seriously, it is binding.)

The Ramah (Choshen Mishpat 209:5) also quotes Terumat HaDeshen (Responsum 320), which states that if - to maintain his reputation - a person goes out and purchases the article that he had sold although he did not own it, the sale is binding.

He is allowed to sell only what is necessary to provide for the immediate necessities for burial - e.g., the grave, the shrouds and the like. Nevertheless, if there is no way that he can sell an article that will provide for this amount exactly, he may sell articles that will bring in a larger sum [Maggid Mishneh; Ramah (Choshen Mishpat 211:2)].

The Nimukei Yosef and Sefer Me’irat Einayim 211:4 state that this leniency is granted only when the son is poor. If he has means, he is not entitled to make such a sale.

The Maggid Mishneh quotes Rav Hai Gaon, who states that he may sell in advance only what he needs for his livelihood for that day. Sefer Me’irat Einayim 211:6, however, interprets the wording u ed by the Rambam a implying that if he lacks food for that one day, he may sell in advance what he needs for many days.

Or any other heir.
The Maggid Mishneh understands this halachah to be a continuation of the principles stated in Halachah 5 and not those stated in Halachah 6. Accordingly, he explains that even the son who sold the property may expropriate it from the purchaser, because the sale was not valid. There is, however a difference. If the son expropriates the property, he must return the money he received from the sale. If the grandson, by contrast, expropriates the property, he is not obligated to return anything. For he is demanding the property on behalf of his grandfather’s estate, and his grandfather is not responsible for his father’s debts.
The Tur and the Shulchan Aruch (Choshen Mishpat 211:3) interpret this as a continuation of the previous halachah. Therefore, it is only the grandson and not the son who can nullify the sale. Moreover, Sefer Me’irat Einayim 221:7 explains that the grandson can nullify the sale without reimbursing the purchaser only when the money was not used for his grandfather’s burial, nor benefited his grandfather in any other way. If the money was used for such purposes, it would have to be returned.

See Chapter 3, Halachot 8 and 9. As stated in those halachot, there are different requirements as to whether or not the movable property being transferred through the kinyan agav must be contained within the landed property. All authorities agree that the giver must possess the movable property at that time (Maggid Mishneh).

The Rambam is obviously speaking of a situation in which the giver no longer desires to give the money, but the recipient is trying to obligate him to do so by virtue of his commitment. Since he is trying to expropriate property from his colleague, the burden of proof is upon him (Maggid Mishneh).

For, unlike the case with a loan, the person to whom it was entrusted either may not use it, or at least may not use it in a manner that will destroy it.

See Chapter 6, Halachah 8, for an explanation of this convention.

See Chapter 6, Halachot 10-12, for an explanation of this convention.

Although the unborn child exists, he is not considered to be a person able to own property until he emerges into the world. See the Rambam’s Commentary on the Mishnah (Bava Batra 9:2).

Even if the person does not formally retract his statements, the fetus does not acquire the property at birth.

A grandson, by contrast, is considered as any other individual [Ramah (Choshen Mishpat 210:1)].

The Maggid Mishneh states that there is a difference of opinion with regard to this matter whether this law applies to all gifts a person makes to his on (as implied by the Rambam’s wording), or only to endowments made by a person on his deathbed through an oral will. The Shulchan Aruch (Choshen Mishpat 210:1) quotes both opinions, but appears to favor the Rambam’s view.

Some authorities require the woman to be at least 40 days pregnant, but the Rambam and the Shulchan Aruch (Choshen Mishpat 210:1) do not make such a distinction.

Since the transfer to the animal or the fetus is not effective. the person cannot acquire property “as they do.”

In this instance, the fact that the animal or the fetus does not acquire anything does not detract from the person’s acquisition.

Bava Batra 147b makes these statements when discussing the limits of the powers of an oral will made by a dying person. Although there are certain extensions granted to a person making such a deposition, he - like any other person - may transfer ownership only of objects of substance.

This law applies even when the produce exists at the time the seller makes this statement. For he is not transferring the produce itself, but rather the right to partake of it. And that is not an object of substance.

This convention is the subject of the following chapter. Through it, the recipient does not become the full owner of the field. He does, however, become the owner of the field with regard to its ability to yield produce. And thus, the produce is his.

Both dedications to the Temple treasury and promises to the poor are considered to be vows.

The Rambam states this entire halachah in Hilchot Arachin Va’Charamin 6:31. Significantly, however, he prefaces his words there with the phrase “It appears to me,” which indicates that the law that follows is based on the Rambam’s logic and has no explicit source in the Talmud or other Rabbinic literature.

The commentaries question the Rambam’s choice of wording, because it is forbidden to consecrate an unblemished animal to the Temple treasury. Instead, it must be offered as a sacrifice (Hilchot Arachin 5:5).

Implied is that although a transaction has not been concluded from the point of view of business law, the individual’s statements have established a personal obligation that is binding upon him.

For a person’s heirs are obligated to carry out his expressed wishes.

The Ra’avad, Rabbenu Asher and the Tur take issue with the Rambam, explaining that when the person says: “I will give such and such to the poor or to the Temple treasury,” he is obligated to uphold his commitment even when the object has not yet come into existence. When, however, a person on his death bed says: “The fruits of this tree should be given to the poor,” he is not bound by a vow, because when the present is to be given, he is no longer alive. Nor is his estate bound by the vow, because the obligation is upon him personally and not on his property.
The Rambam differs and maintains that since the deceased person obligated himself by making a commitment, the obligation becomes incumbent on his heirs as if they had taken the vow themselves (Kessef Mishneh). The Sliulchan Aruch (Choshen Mishpat 212:7) follows the Rambam’s view, while the Ramah folJows that of the other authorities.

Hilchot Arachin 6:31-33.