Rambam - 1 Chapter a Day

Taking hold of the object thus serves as a kinyan, giving the person who does so the right of ownership.

It appears that the Rambam is speaking in this clause about objects that are declared ownerless by their owners, as mentioned in Hilchot Nedarim 2:14.

See Hilchot Gezelah Va’Avedah 6:13. In contrast, objects belonging to other men found in such places may have to be returned to their owners.

With regard to Eretz Yisrael, the Ra’avad differs with the Rambam and maintains that the land was divided among the tribes, and each tribe became the owner of the natural resources in its ancestral portions. Thus, every member of that tribe is allowed to take from these resources, but not so a member of another tribe.
From Hilchot Nizkei Mammon 5:3, it would appear that the Rambam maintains that every person has a right to these resources, although they have been granted to a particular tribe, provided he does not use those resources for commercial enterprise (Maggid Mislmeh). The perspective of the Maggid Mishneh is not, however, accepted by all authorities.
Shulchan Aruch HaRav (Choshen Mishpat, Hilchot Hejker 2) emphasizes that these laws apply to a wilderness in which no government has asserted its authority. If, however, a government has asserted its authority over land, it becomes the legal owner of the land, and its rights must be respected.

For he is not allowed to enter property belonging to a colleague without that colleague’s permission (Maggid Mishneh).

Because the field is not a protected courtyard, nor is the owner standing next to it. See Halachah 4 and notes (Maggid Mishneh).

The rationale is that a vivarium is considered to be a protected courtyard, for the animals inside cannot break out. Therefore, even a wild animal that enters from the outside is acquired by its owner (Maggid Mishneh).

For he takes property belonging to a colleague by force. As emphasized by the contrast to the following halachah, here the Rambam’s statements apply according to Scriptural Law. Thus, the worth of the animal can be expropriated by the owner of the vivarium through legal process.

See Hilchot Shabbat 10:19-20. Since the animal cannot leave the confines of the vivarium, the fact that effort is required to snare him is not significant.

I.e., the person is not considered to have acquired the animal in his snare according to Scriptural Law. Therefore, the prohibition is only Rabbinic in origin, and the person who owns the snare cannot expropriate the value of the animal trapped through legal process (Hilchot Gezelah Va’Avedah 6:12).
The Rabbis instituted this prohibition as a reflection of “the ways of peace” - i.e., to prevent strife from arising.

I.e., it has a receptacle.

For a container belonging to a person acquires property on his behalf according to Scriptural Law. Hence, “the value of the animal can be expropriated through legal process” (Ra’avad).

A field is considered to be an “unprotected courtyard.” If a courtyard is protected and another person snares an animal there, it becomes the property of the owner of the courtyard, even though he is not present and does not state his intent to acquire the animal [Maggid Mishneh; Ramah (Choshen Mishpat 273:14).

The owner acquires the animal by virtue of its presence in his field. This kinyan is applicable according to Scriptural Law, since the animal is trapped and cannot move. [See Hilchot Gezelah Va’Avedah 17:11. With this explanation, the objections of the Ra’avad are resolved.]
The owner of the trap, by contrast, has a right to the animal only by virtue of Rabbinic decree. In this instance, the Rabbis did not ordain that their decree supersedes Scriptural Law and applies to property belonging to another person.

In such an instance, the owner of the courtyard acquires an article placed within, even when he is not standing next to his courtyard, and does not declare his desire to acquire it.

When an object is moving, even if it can be considered to be a courtyard, its owner does not acquire an object placed within it. See Hilchot Mechirah 3:13; Hilchot Gerushin 5:17.

Even if the convert had fathered children before he converted and they converted together with him, they are not considered to be his heirs. This applies even when the convert’s wife converts while pregnant with the child, or the convert fathered a child with a Jewish woman while he was a gentile. (See Bava Batra 149a.)

Moreover, since his sons whom he fathered as a gentile are not his legal heirs, he may not allocate property to them using the mechanism of a matnat sh’chiv me’ra (Ibid.).

See Hilchot Sh’chenim 12:5, which explains that when a person sells property, a neighbor is given the right to buy the property at the purchase price from the purchaser.

As stated in Hilchot Sh’chenim 13:1, when a person receives property as a gift, the neighbor is not given the right to buy it from him. The rationale is that property that is purchased can be purchased in another location as well. Therefore, we require the purchaser to seek out another location in consideration of the neighbor. There is, however, no way a person can guarantee that property will be given to him as a gift in another place. Therefore, the neighbor is not granted this privilege. Similarly, in the present instance, there is no way that we can guarantee that the person will be able to acquire ownerless property again, and so the neighbor is not granted the privilege of purchasing it from him (Lechem Mishneh).

When a person acquires several fields from a colleague because of a sale or a gift, through the acquisition of one he acquires the other (Hilchot Mechirah 1:19-20). This does not apply in the present instance. The difference between the two instances is that with regard to a sale, the transaction is dependent on the seller’s intent to transfer his property - to which there is no parallel in the present instance (Maggid Mishneh).

I.e., our Sages (Bava Batra 53b) did not resolve the question whether this action is sufficient to acquire both fields.

The second person is considered to have a stronger claim, because there is no question that his action is sufficient to acquire ownership of the field (Maggid Mishneh) .

With regard to this point, the Tur and the Ramah (Choshen Mishpat 275:10) differ and maintain that if he manifests ownership over the inner house with the intent of acquiring both it and the outer house, he acquires them both. Sefer Me’irat Einayim 275:15 explains that since one must walk through the outer house to reach the inner house, the outer house can be considered to be subordinate to it.

See the gloss of the Siftei Cohen 275:4.

Since there is no one transferring the deed to him, the deed is no more than a record of the convert’s acquisition of the property.

I.e., it is no more valuable than any other used piece of paper.

With regard to a sale, by contrast, he may acquire many fields by manifesting ownership over one. And he may acquire an entire field even if it is not distinctly marked.

For by plunging in the spade, he manifests ownership over the field. It is not necessary to manifest ownership over every portion of the field individually - once he acquires one portion, he acquires the entire field.

Since the boundaries of the field are not defined, when the person manifests his ownership of the field, it is not clear - to himself or to others - what he is acquiring. Therefore, we assume that he acquires only that portion of the field that he would plow at one time (Kin’at Eliyahu).

I.e., when threshing with a team of oxen, it is common to proceed for a certain length and then to return. The person who plunged in the spade acquires that measure of land. See also the notes on Halachah 13, where important insights applicable to this halachah are stated.

This term refers to a plant or tree with very long and powerful roots. Joshua planted it in Eretz Yisrael to distinguish the boundaries of the ancestral portion of one tribe from another [Bava Batra 56a; Rambam’s Commentary on the Mishnah (Kilayim 1:8)]. Sefer Me’irat Einayim 275:5 explains that it was also used to distinguish between properties owned by individuals.

Since these are clearly evident boundaries, even if the borders of the convert’s field extend beyond them, the person does not acquire any land beyond them.

See Hilchot Matnot Aniyim 3:1, which explains that when a field is divided by certain entities - e.g., a river or an irrigation ditch - pe’ah, a portion of the crop left at the edge of the field for the poor - must be left at the sides of both divisions. It is not sufficient to leave a single amount.

The Rambam’s thesis is that whenever in some manner the two portions of the field are considered to be distinct, they are considered to be distinct with regard to [the acquisition of] the property of a [deceased] convert.
There is no explicit Rabbinic source for the Rambam’s opinion. His decision is an inference from Bava Batra 55a, which states:
A boundary marker and a chatzav constitute a distinction with regard to [the acquisition of] the property of a [deceased] convert, but do not constitute a distinction with regard to pe’ah and ritual impurity.
When Ravin came, he said in the name of Rabbi Yochanan: “They constitute a distinction with regard to pe’ah and ritual impurity, but do not constitute a distinction with regard to the Sabbath.”
Ravva declares: “[They constitute a distinction] even with regard to the Sabbath.”
The Rambam maintains that since there is a discussion of whether or not these articles that are sufficient to create a distinction with regard to the acquisition of the property of a deceased convert are sufficient to create a distinction in the other contexts, the distinctions that are effective with regard to the other contexts are of greater halachic significance. Therefore, they are also effective with regard to the acquisition of the property of a deceased convert (Maggid Mishneh).
The Ra’avad differs with the Rambam’s rulings in this and the following halachah. The Shulchan Aruch (Choshen Mishpat 275:5-6) quotes the Rambam’s rulings. Note also the gloss of the Lechem Mishneh, which raises questions based upon the Rambam’s rulings in other sources.

On the Sabbath, if one brought an article from one public domain to another through a carmelit, one would not be liable (Hilchot Shabbat 14:14). Thus, the carmelit creates a distinction.
The commentaries, however, note that there is an apparent contradiction between this halachah and Hilchot Shabbat 18:24.

See Hilchot Gerushin 5:9, which speaks of a husband’s granting a portion of his property to his wife so that she can acquire the bill of divorce.

Thus, it would not be included in the person’s acquisition of the field.

The Ra’avad objects to the Rambam’s ruling on the basis of Bava Batra 56a. Indeed, even the Maggid Mishneh and Kessef Mishneh, who support the Rambam’s ruling, note that it appears to contradict Halachah 10, which states that if one digs in one field with the intent of acquiring it and another field, one does not acquire the other field.
The Maggid Mishneh distinguishes between the two rulings by explaining that digging is not a totally effective means of manifesting one’s ownership. In this halachah, we are speaking of a different and more involving means of manifesting ownership, as explained in Chapter 2.
The Kessef Mishneh explains that the difference depends on the person’s intention. In Halachah 10, the person had a general intent to acquire the convert’s property, but did not have a specific intent to acquire both fields. In this instance, he had the intent of acquiring all the fields owned by the convert in this valley.
The Ra’avad and the Tur differ with the Rambam’s conception and maintain that the above applies only in a field that requires irrigation. In a field that is watered by the rain, different rules apply. The Shulchan Aruch (Choshen Mishpat 275:7) quotes the Rambam’s ruling, while the Ramah cites that of the Tur.

The Rambam mentions the preliminary concepts in this halachah in this chapter, only because of the final clause, which relates to the acquisition of property from a deceased convert.

Our translation, though not reflecting the literal meaning of the words used by the Rambam, is based on the interpretation of both the Maggid Mishneh and the Kessef Mishneh. The laws regarding the acquisition of movable property through meshichah and the payment of money are discussed in Hilchot Mechirah, Chapter 3.
There the Rambam explains that, although according to Scriptural Law, movable property is acquired through the transfer of money, the Rabbis instituted the kinyan of meshichah (drawing the article from place to place). According to the Rambam, this applies only with regard to a Jew, and a gentile can acquire movable property through the transfer of money. This conception is also reflected in the Rambam’s decision in Hilchot Bechorot 4:5.
The Ramban and other authorities differ and maintain that even for a gentile, the transfer of money is not an effective kinyan. See the glosses of Sefer Me’irat Einayim 194:1, Siftei Cohen 194:1. The Lechem Mishneh indeed notes that from the Rambam’s ruling in Hilchot Avodat Kochavim 7:5, it would appear that the Rambam also accepts this thesis.

The commentaries explain that the Rambam is referring to his ruling (Hilchot Mechirah 1:17) that states that a gentile may not acquire land by manifesting his ownership over it. The rationale is, as explained by the Maggid Mishneh in that source, that if this were allowed, it might lead to gentiles’ taking property by force.

I.e., until he has a legal document that will be honored by a court of law, the purchaser will not consider the transfer of property to be complete, for he will suspect that the seller might withhold the property from him.

From the Rambam’s wording, it is apparent that he maintains that if the purchaser manifests ownership over the property before the other person, the purchaser acquires it. This ruling is not accepted by the Ra’avad, the Rashba and the Tur, who maintain that since the purchaser desired to acquire the property via the transfer of a deed of sale, it is only through such a transfer that he can acquire it. Therefore, even if the purchaser manifests his possession over the property first, if the second person manifests possession before the deed of sale is transferred, the second person acquires it.
The Shulchan Aruch (Choshen Mishpat 194:2) follows the Rambam’s ruling, while the Ramah cites that of the other authorities.

The Ramah (op. cit.) states that the person who acquires the land is considered wicked. Nevertheless, the purchaser is forbidden to try to retake the land from him with the help of the gentile.

I.e., only when there is no binding secular law, is the ruling of Torah law applied. Otherwise, Torah law itself accepts its limits and allows for its ruling to be preempted by secular law.

See Hilchot Gezelah, Chapter 5, where this concept is explained at length.