Shabbat - Chapter Ten

A knot that requires professional expertise and cannot be tied by an untrained person.

The fishermen who would catch chilazon that were necessary for the construction of the Sanctuary would tie their nets with special knots that required professional expertise. Similarly, these knots were intended to remain permanently. Therefore, tying such a knot is considered a category of forbidden labor.
It must be emphasized that Rashi and Rabbenu Asher do not accept the criteria mentioned here by the Rambam (which are based on the Halachot of Rabbenu Yitzchak Alfasi from Shabbat 111 b ). They maintain that tying a knot with the intention that it remain permanently causes one to be liable if the knot is strong enough to remain, even though tying the knot does not require professional expertise.
The Shulchan Aruch (Orach Chayim 317:1) follows the Rambam’s perspective. The Ramah, however, rules according to the view of Rashi and Rabbenu Asher.

According to Rashi and Rabbenu Asher, one would be liable for tying such knots.

Rabbi Y osef Korcus explains the difference between the two clauses of this halachah. Since the knots mentioned in the first clause are intended to last permanently, one would think that one is liable. Therefore, the Rambam emphasizes that one is not.
By contrast, since the knots mentioned in the second clause are not intended to last permanently, one would think that it is permitted to tie them. Hence, the Rambam emphasizes that this is forbidden.

This law—and most of the subsequent clauses of this halachah—are based on Shabbat 15:2. In each of the clauses, the Rambam (based on the Talmud) further develops the concepts stated in the Mishnah.
ln this instance, Shabbat 112a explains that such a cloak had two straps, each one extending from one corner of the garment to the other. Since a woman could remove the garment by untying only one strap and slipping it over her head, there is reason to think that one of the knots would be considered as perm.anent, and therefore forbidden to be tied on the Sabbath. Nevertheless, this hypothesis is not accepted, and tying and untying both knots is permitted.

Shabbat (loc. cit.) relates that these nets are also tied to a woman’s hair. Hence, since the net is not tight fitting, it could be slipped off without untying it. Thus one might consider the knot as permanent. Nevertheless, since usually, these nets are untied, there is no difficulty in tying them.

Since they will be untied when the shoes are removed, tying them is permitted.

Shabbat (loc. cit.) explains that the pouches were tied at each of these protrusions. Although the liquid could be removed by opening only one of them, neither of the knots is considered to be permanent, because it was customary to open both knots, for then the liquids flowed more freely.

Shabbat (loc. cit.) states that although the food could be removed from the pot without untying the knot, we do not consider the knot permanent. We assume that . the people will follow the usual practice and untie the knots before opening the pot.

It is forbidden to tie a bucket with an ordinary rope, because it is likely that one will leave the rope there permanently. A linen cord, a belt, or another similar entity is not really fit for this purpose. Hence, it is probable that one will untie it after using it (Maggid Mishneh, based on Shabbat 113a).
Even though the Rambam would maintain that tying an ordinary rope to a bucket does not make one liable according to Torah law·, there is still reason for this additional decree.

The animal’s owner closed the stall by tying a rope before it, tying it to both ends of the entrance (or, according to other commentaries, by tying two ropes). Although the stall could be opened by untying only one knot, we do not assume that the rope(s) will be left there permanently (Shabbat 112b ).

This phrase is the key to the Rambam’s understanding of this law (which is based on Shabbat 113a). Since tying the animal does not necessitate using a knot that requires professional expertise, the Rambam would not consider it prohibited according to Torah law. And as the Rambam states, since the intention is not to leave the animal tied permanently, there is no reason for even a Rabbinic prohibition. Nevertheless, since it is forbidden to use a rope on the Sabbath unless it was designated for use beforehand, one may not bring a rope from home. If one tied the rope to the animal or to the feeding trough before the commencement of the Sabbath, however, it is obvious that one intended to use it on the Sabbath.

Shabbat 146a explains that dates and dried figs we1·e strung on a cord and placed in palm branch baskets. One may untie the basket~ and cut the cords and eat the fruit.

Other substances fit for tying would be muktzeh, forbidden to be carried on the Sabbath.

In his Commentary סri the Mishnah (Shabbat 24:5), the Rambam explains that a reed will never be used to tie a permanent knot.

This halachah is based on Shabbat 112a, which relates that Rav Yirmiyah saw Rabbi Abahu act in this manner when his sandal strap snapped on the Sabbath. That narrative took place in a carmelit.
The Talmud continues mentioning a situation where Abbaye’s sandal strap snapped in a private courtyard and Rav Yosef forbade him to employ a similar technique. The Shulchan Aruch (Orach Chayim 308:15) mentions both these rulings.

In his gloss on the Shulchan Aruch (Orach Chayim 317:2), the Ramah mentions that this is permitted only when it does not involve much effort.

The Magen Avraham 317:8 states that were one to tie a knot, it would be forbidden, because we can assume that the knot would be left permanently.

The Ramah (Orach Chayim 317:5) states that one may even tie a single knot with a loop above it, provided one does not intend to leave it permanently. See Shulchan Aruch HaRav 317:3, Mishnah Berurah 317:29.

I.e., there is no reason to decree that a loop is forbidden, lest one tie a knot.

The Kessef Mishneh objects to the Rambam’s decision, noting that Shabbat 113a states that if one employs a linen cord, one may tie a knot, but if one employs a rope, one must tie a loop. In his Shulchan Aruch (Orach Chayim 317:4), Rav Yosef Karo rules according to his understanding of that passage.
Yad David and others reconcile the Rambam’s wording, explaining that he means “wind a linen cord around it, or tie it [i.e., the rope itself] with a loop.”

In his Cc,mmenta1·y on the Mishnah (Shabbat 24:5), the Rambam states that leniency was granted with regard to tying knots that are intended to remain permanently if they are tied for the sake of a mitzvah on the Sabbath. Rashi, by contrast maintains that the Mishnah grants leniency with regard to measuring alone and not with regard to tying knots that are not temporary in nature.
On this basis, this halachah must .be interpreted to mean that one is allowed to tie knots that will not remain permanently, even with a knot that requires professional expertise, or a knot that is intended to remain for an extended period if it does not require professional expertise. (See the Be’ur Halachah 317.)

The concluding Mishnah in the tractate of Shabbat states that “In the days of Rabbi Tzadok’s father and Abba Shaul ben Botnit, they ... tied a cup with a reed to ascertain whether a vat possessed an opening that was a handbreadth in size.”

This is not considered a permanent knot, because we assume that after the Sabbath it will be changed. There are opinions in the Talmud (Eruvin 102b) that permit only a loop to be tied. Based on the principle, “Restrictions in the category of sh’vut are not enforced in the Temple,” the Rambam, however, chooses the more lenient view (Kessef Mishneh, Or Sameach).

Just as tying is one of the 39 categories of forbidden labor, so is untying. Accordingly, all the principles described above concerning tying apply with regard to untying.

Tosafot (Shabbat 73a) states that one is liable only when one unties with the intent of retying, for this was the practice of the chilazon fishermen in the construction of the Sanctuary. Significantly, the Rambam does not mention that requirement. Rashi (Shabbat 74b) rules more stringently, holding one liable even when one does not have the intent of retying the knot immediately. Needless to say, even according to Rashi’s view, one must untie the knot for a positive purpose.

Our translation is based on Rav Kapach’s version of the Rambam’s Commentary on the Mishnah (Keilim 17: 17).

The commentaries question why this activity is not considered a derivative of the forbidden labor of spinning thread. The Migdal Oz resolves this question by citing as a source the Jerusalem Talmud, Shabbat 15:1. That passage relates that an experienced tailor connects two ends of a thread together by undoing their twine, and then rewinding them. Since the tailor’s object is to connect the two ends, the activity is considered a derivative of tying.

See Chapter 9, Halachah 13 and Halachah 1 of this chapter.

See Chapter 1, Halachot 17-18.

This is one of the 39 categories of forbidden labor.

Many of the commentaries question why the Rambam does not mention that the person is also liable for tying. It would appear, however, that this knot does not require professional expertise. Furthermore, sewing and not tying, is the subject of the Rambam’s statements here.

Only if the stitches are tied at both ends will they remain permanently. Rav Kapach notes that in Hilchot Kilayim 10:24, the Rambam does not require the two stitches to be attached for one to be liable for sha’ atnez, echoing a similar ruling of the Mishnah (Kilayim 9: 10).
Rav Kapach explains that the obligations of the two prohibitions differ. With regard to sha’ atnez, there is no requirement that wool and linen be permanently attached for one to be liable. In contrast, if the forbidden activity one performs on the Sabbath is not lasting in nature, one is not liable.

After one sews several stitches, one pulls the thread taut (Shabbat 75a).

Our translation is based on the gloss of Rabbi Akiva Eiger.

This is one of the 39 categories of forbidden labor. Although this activity was performed in the Sanctuary for this purpose, the Rambam maintains that a person who performs a הפוגל הכירצ הניאש הכאלמ is liable. Therefore, he maintains that one is liable even if he tears for other purposes. The Mishnah (Shabbat 7:2), however, describes this forbidden labor as “one who tears to sew two stitches.”

See Chapter 1, Halachot 17-18.

The Rambam discusses the obligation to rend one’s garments over a deceased person in Hilchot Eivel, Chapters 8 and 9.

See Chapter 8, Halachah 8, and notes.

The Merkevet HaMishnah states that this refers to simply opening up a place for the head in a garment. Since the Rambam maintains that a person who performs a ל הכירצ הניאש הכאלמ is liable, he maintains that a person is liable for cutting such an opening even if he does not sew it.
Rashi (Shabbat 48a) states that one is liable for this activity for performing a derivative of the forbidden category of labor שיטפב ,חנמ making an entity ready for use. (Rashi cannot hold one liable for tearing, since he differs with the Rambam and maintains that a person who performs a הפוגל הכירצ הניאש הכאלמ is not liable.)
The latter interpretation is reflected in the statements of Rabbenu A vraham, the Rambam’s son, quoted in the Ma’ aseh Rokeach, which explain that after a garment was completed, the neck was sewed up with temporary stitches to show that it was never worn. When the purchaser desired to put on the garment, these stitches were undone. See also Shulchan Aruch and Ramah (Orach Chayim 317:3).

For just as a person who sews, he attaches two entities to each other.

See the magen Avraham 340:18, which states that the entities one separates must have been attached to each other with the intent of remaining permanently. Based on a similar rationale, the Chacham Tzvi (Responsum 39) does not hold one liable for opening an envelope, since the flap is not intended to remain permanently closed.
There is a common application of this principle today: the use of disposable baby diapers. Since the flap is not intended to remain permanently closed, fastening it or unfastening it is not considered as related to the forbidden labors of sewing and tearing.

This is one of the 39 categories of forbidden labor. One is liable for even the smallest act of construction, because if there was even the slightest nick or hole in one of the walls of the Sanctuary, hot lead would be poured into it to fill it (Shabbat 102b).

For building, since with this activity, he prepares the building’s floor. As mentioned in Chapter 8, Halachah 1, a person who performs this activity in a field is liable for plowing.
Significantly, based on Rashi (Eruvin 104a), Shulchan Aruch HaRav 313:24 also holds one liable for performing a derivative of building when one levels the ground in one’s yard.

Without the mortar, the stones would not hold in place.

As the source for this halachah, the Maggid Mishneh points to the following passage from the Jerusalem Talmud (Shabbat 7:2, 12:1):
Where was [the forbidden labor of] building found in the Sanctuary? In the placement of the boards in their sockets.
1s this meant to imply that building on a base of utensils is considered building? The sockets are considered as the ground.
From this passage, it is clear that.building on a base of utensils is not considered to be building according to Torah law. Note that this law refers to constructing a building by using a utensil as a base. The discussion of whether fashioning a utensil or connecting its parts is a derivative of the forbidden labor of building is discussed in the following halachah and notes.

The commentaries question why the erection of a tent is merely given the status of a derivative and is not considered to be a הכאלמ ןיעמ of the forbidden labor of building. The Fnei Yehoshua (Sukkah 16b) explains that a building is a stable structure, while a tent is far more fragile in nature.
The Even HaEzel explains that building involves two actions:
a) joining separate entities into a single whole;
b) spreading a roof over a structure.
Constructing a structure—or part of a structure—which contains both these actions is considered to be building proper. If either—but only one—of the two is involved, the act is deemed a derivative. Thus, erecting a tent is considered a derivative, because it involves spreading a roof, and making cheese is considered a derivative, because it involves joining separate entities into a single whole.

Significantly, neither in this halachah nor in Chapter 22, Halachah 27, when he mentions the Rabbinic prohibition against erecting a temporary tent does the Rambam explain wl1ether the concept of permanence depends on the strength of the structure or the intent of the builder. It appears that he relies on his statements in Chapter 9, Halachah 13, “Whenever one performs a labor that does not have a permanent effect on the Sabbath, one is not liable.” (See the notes on that halachah.)

Beitzah 22a relates a difference of opinion between the School of Hillel and the School of Shammai. The School of Shammai maintains that one is liable for performing a derivative of the forbi.dden labor of building when fashioning a utensil, while the School of Hillel rejects this thesis: “There is no [ concept of] building with regard to utensils.”
There is, however, a difference of opinion between the Rabbis about the interpretation of this statement. Rashi understands the statement simply. Fashioning a utensil can never be a derivative of building. One is liable for making a utensil, but one’s liability stems from the forbidden labor of שיטפב ,חנמ completing a utensil. This view is shared by Rav Hai Gaon, Rabbenu Yitzchak Alfasi (according to Rabbenu Nissim), and others.
As obvious from this halachah, the Rambam differs and maintains that one is liable for building when fashioning a utensil. The leniency mentioned by the School of Hillel refers only to putting together a utensil that is made up of several component parts. [This is, however, forbidden by Rabbinic decree, because it resembles building (Chapter 22, Halachah 26).] Fashioning a new utensil, by contrast, is surely considered a derivative of building.
This latter opinion is shared by Tosafot (Shabbat 74b), the Ramban, the Rashba, and others. It is also accepted by the Shulchan Aruch (Orach Chayim 314:1).

See Chapter 7, Halachah 6.

Although one is liable for building even the slightest amount, with regard to this derivative the minimum measure for which one is liable is the size of a dried fig—the minimum measure associated with the labors related to food. Unless one makes an amount of cheese that size, one’s activity is not significant at all.

The Rambam discusses the Rabbinic prohibitions associated with this activity in Chapter 22, Halachah 25. (See also the discussion of the issue in the Shulchan Aruch [Orach Chayim 313:9] and commentaries.)

Note that in Halachah 16, the Rambam states that one who makes a hole in a building is liable for performing a derivative of the forbidden labor of שיזפפב .חנמSimilarly, in Chapter 23, Halachah 1, he states that a person who makes a hole in a chicken coop for the sake of letting light in and letting foul air out is liable for performing a derivative of the forbidden labor of שיזפפב .חנמ
Among the resolutions offered is that in addition to being liable for שיזפפב ,חנמ one is liable for building (Lechem Mishneh). Alternatively, in this halachah, the Rambam mentions making a hole of any size, while in Chapter 23, he mentions making an opening, implying that it is of a larger size, and only then is one liable for .(Sefer HaKovetz) חנמ שיזפפב

These doors serve as part of the floor of the building. Therefore, putting them in place is a derivative of building. (See also Chapter 22, Halachah 25, and the commentary of the Maggid Mishneh.)

Whenever the encampment of the Jewish people moved, the Sanctuary was taken down and then reconstructed in the new camp (Shabbat 31b).
The commentaries note that in Chapter 1, Halachah 18, the Rambam mentions that one is liable for “demolishing to build in its place,” while in this halachah, the words “in its place” are not mentioned.

As mentioned in Chapter 1, Halachah 17, one is not liable for performing any forbidden labor with merely a destructive intent. Nevertheless, as mentioned in Chapter 8, Halachah 8, if one destroys with the intent of venting one’s anger, one is liable. Seemingly, the Rambam should have mentioned this point in this context as well.

The Maggid Mishneh explains that the Rambam’s intent is to illustrate how one is liable for demolishing for performing the converse of every positive activity for which one is liable for building.
Perhaps the Rambam’s wording also alludes to the concept that a person is liable only when he demolishes a structure that is strong enough to last. If the structure he demolishes is not that sturdy, he is not liable. See Shulchan Aruch HaRav 313:19.

In his Commentary on the Mishnah (Shabbat 7:2), in definition of this category of forbidden labor, the Rambam writes:
A person who beats [an article] with a hammer, even at the conclusion of the work as the craftsmen do. They strike very light blows to straighten the surface of a utensil .... Therefore, every activity involved in fashioning and completing a utensil, planing it, polishing it, and making it attractive are all derivatives of dealing [the final] hammer blow.
This is what [our Sages implied with] their statement (Shabbat 75b), “For any activity that constitutes the completion of a task, one is liable for dealing [the final] hammer blow.”

Tosafot, Shabbat 74b, asks: Since glass utensils are fashioned by blowing, why is one not liable for building as one is for making any other vessel? (See Halachah 13.) lndeed, the Jerusalem Talmud (Shabbat 7:2) holds a person who blows a glass utensil liable for performing that forbidden labor.
The Yesodei Yeshurun and Rav Kapach point out that Rashi (Shabbat 75b) explains that the activity referred to involves cutting a glass utensil by exposing it to a current of air. This is also implied by the Hebrew words תיכוכז ילכב חפנמה—“one who blows at a glass utensil.”

If, however, one makes a drawing or a design on a paper (or on a similar substance), one is liable for performing a derivative of writing or dyeing (Jerusalem Talmud, Shabbat 7:2). (See also Chapter 11, Halachah 17, and Be’ur Halachah 340.)

The Maggid Mishneh in his gloss on Chapter 11, Halachah 7, renders the term used in our halachah as ,ררגמ “scrape.”

See also Chapter 23, Halachah 4.

I.e., to cause one to be held liable, any opening must be fit to be used as an entrance through which entities are brought in, and an exit through which entities are taken out.

The Ra’avad, Rashi (Shabbat 107a), and others maintain that performing this activity is a derivative of the labor of building. The Ziv HaMishnah explains the Rambam’s position, focusing on the words “for this is a labor performed by a physician”—i.e., one is not building a structure, but completing a specific labor that physicians perform.

I.e., one may perform the act without any compunctions (Shabbat 107a). Although the Rambam’s ruling is quoted by the Shulchan Aruch ( Orach Chayim 328:28), Shulchan Aruch HaRav 328:32 and the Mishnah Berurah 328:88 suggest that it is preferable to have this act performed by a gentile.
According to Rashi and many other authorities, this activity is permitted, because it is a הפוגל הכירצ הניאש .הכאלמ Although generally there would be a Rabbinic prohibition against such an act, in this instance, no prohibition was enforced because of the suffering involved.
This explanation is, however, untenable for the Rambam, for as explained in Chapter 1, Halachah 7, he holds one liable for performing a הפוגל הכירצ הניאש .הכאלמ Among the explanations given for the Rambam’s position is that in removing the pus one does not complete the task involved, for an opening sufficient to be useful for another purpose has not been made (Maggid Mishneh). Similarly, Sefer HaBatim explains that in removing the pus, the person thinks only of relieving his pain and does not have any intent of making an opening. Thus the situation differs from the examples stated in Chapter 1, where the person performed the forbidden activity intentionally.
See also the commentary of Rav Chayim Soloveichik who explains that this decision is not dependent on the principle of הפוגל הכירצ הניאש ,הכאלמ but rather on the concept of ךירונתמ וניא (see Chapter 1, Halachot 5-6) that a person who performs an activity which unintentionally causes a forbidden labor to be performed is not liable.
Although the Rambam agrees that when it is certain that one’s actions will result in the performance of a forbidden labor, one is liable, the latter principle does not apply when one does not appreciate the results of the performance of the forbidden labor היל( אחינ אלו אשיר .)קיםפ In such an instance, the Rambam follows the opinion ot· the Aruch who maintains that one is not liable.

Our translation is based on the Rambam’s Commentary on the Mishnah (Shabbat 12:1), where he explains that this refers to “smoothing it with a tool known to be used for this purpose.” Rashi (Shabbat 102b) renders this term as “chisel.”

The Or Sameach (based on Shabbat 102b) states that this applies only in setting the stones of a building’s foundation, and not those of its walls.
One might ask: Why is the person who performs this activity not liable for building (see Rashi and Tosafot, Shabbat, loc. cit. )? It is possible to explain that it goes without saying that the Rambam would hold such an individual liable for building, the new concept taught by this halachah is that he is also liable for dealing [the final] hammer blow.

Our translation is based on the commentary ofRabbenu Chanan’el on Shabbat 75b.

The Kessef Mishneh explains that this means that the person removes them from the garment with the intention of making it more attractive, even though he could wear the garment while they are still adhering to it. This interpretation is quoted by Shulchan Aruch HaRav 302:7 and the Mishnah Berurah 302:10.

As explained in Chapter 1, Halachah 11, a person is not liable for performing a forbidden activity as a קסעתמ—i.e., without consciously controlling his behavior. In this instance as well, it is common for people to pick at their clothes, without giving the matter any thought at all.

It is, nevertheless, forbidden according to Rabbinic decree (Shulchan Aruch HaRav 302:6, Mishnah Berurah 302:11).

The early manuscripts and printings of the Mishneh Torah state ןבלח .בוהיצה Based on the dictionary of Rabbi Tanchum of Jerusalem, this term is interpreted to mean “bright white threads.”

Based on Shabbat 147a, the Ra’avad, Rashi, and others, interpret this as shaking dew from a new garment, and the activity being a derivative of the forbidden labor of whitening. This interpretation is accepted by the Shulchan Aruch ( Orach Chayim 302: 1 ).

Rav Sa’adiah Adana explains that according to the general principles the Rambam outlined in the beginning of the text, it would have been sufficient for him to state “is liable,” as is his practice throughout the text. Nevertheless, in this instance he quotes the Sages’ expression (Shabbat 147a), “is liable for a sin offering”; because of the nature of the activity, one might think that one is liable only for stripes for rebelliousness, the punishment given for violating a Rabbinic decree.

See Halachah 24, where the Rambam mentions some of the species not included in this category.

The commentaries note that Shabbat 106b differentiates between a רורד רופצ—a swallow—and other fowl. On this basis, the Shulchan Aruch (Orach Chayim 316:1) states that other birds are also considered trapped when enclosed in houses, and it is only a swallow—because it is small—that must be trapped in a closet.
The Merkevet HaMishneh and others explain that Rabbenu Yitzchak Alfasi and the Rambam interpret the conclusion of that Talmudic passage as indicating that there is no difference between one type of fowl and another. It is too difficult to trap any bird when enclosed in a house.

This is one of the 39 categories of forbidden labor.

The Hebrew תיב usually means house. Here, however, it refers to a one-room structure.

The commentaries explain that a deer is trapped even when there are open windows and when there is no roof.

See Hilchot Sh’vitat Yom Tov 2:7, where the Rambam develops this principle.

The Maggid Mishneh states that this means “without having to pause.”

Leviticus 11:29. See Chapter 8, Halachah 9, for a definition of the species referred to.

The distinction between the eight species mentioned in the Torah and other crawling animals is relevant within the context of the Mishnah, Shabbat 14: 1, which follows the view of Rabbi Shimon that one is not held liable for performing a [forbidden] labor when he has no need for the actual labor he performed. Hence, it is necessary to differentiate between the eight species mentioned in the Torah (which are generally trapped for their hides) and other crawling animals when that is not necessarily the case.

This ruling depends on the principle stated by the Rambam immediately afterwards, that one is held liable for performing a [forbidden] labor when he has no need for the actual labor he performed.

This subject, referred to as a הפוגל הכירצ הניאש הכאלמ in Hebrew, is discussed at length in Chapter 1, Halachah 7. As mentioned, there are many authorities who differ with the Rambam’s opinion on this issue.

As obvious from Halachah 24, a person who traps an animal that is physically disabled is not liable. Shabbat 106b differentiates between the animals mentioned in that halachah and those mentioned in this halachah as follows: An animal that is sleeping or blind is sensitive to man’s steps. Unless he approaches stealthily, the animal will be startled and flee. In contrast, those mentioned in Halachah 24 will not be able to escape capture.

Note the Maggid Mishneh, who quotes Rabbenu Chanan’el’s commentary, which explains this as a continuation of the concepts mentioned in the previous halachah. Rashi (Shabbat 106b) interprets the passage differently. (See the Be’ur Halachah 316.)

The Ramah (Orach Chayim 316:2) emphasizes that even during the week, this behavior is undesirable. In his Darchei Moshe, he emphasizes that such cruelty will prevent a person from participating in the feast of the Leviathan in the era of the redemption.

The Magen Avraham 316:4 emphasizes that if the person merely sends out the dogs and is not personally involved in the deer’s capture, he is not held liable at all. There is, however, a Rabbinic prohibition involved.

Here, we have chosen to translate the Hebrew לענ as “close,” rather than “lock.” Closing the door is sufficient to confine the deer inside and cause one to be liable for trapping it.

Although he did not actively pursue the deer into the room, since it becomes trapped through his deed, he is responsible.

This halachah illustrates the principle stated in Chapter 1, Halachot 15-16:
Whenever two people share in the performance of a [forbidden] labor that one of them could have performed by himself, they are [both] free of liability .... When, however, a single individual cannot perform [the forbidden labor] alone and must be joined by others, [all the individuals involved are held liable].
See Sefer HaKovetz and others for explanations why this is not a mere reiteration of the principles stated previously.

The first person’s act did not obstruct the deer’s escape, while the second person’s did. Although the first person assisted the second, since his assistance was passive—he did absolutely nothing—he does not share in the liability. Furthermore, as the Rambam states in his Commentary on the Mishnah (Shabbat 13:7), he is permitted to remain seated.

For he completed the capture of the animal by sitting down. This is a fait acccompli to which the second person adds nothing.

Without moving.

He may not, however, take the deer on the Sabbath itself. Although it is already trapped, it is muktzeh, forbidden to be handled. (See Chapter 25, Halachah 26.)

In this instance, we have translated the Hebrew לענ as “lock” rather than “close” as above. Were a person to close the door and thus trap the deer, he would be liable. The Rambam is speaking of a situation where the deer was trapped previously (in the analogy, by the first person) and then locked in (blocked further by the second person).

In this instance as well, it is forbidden to take the bird on the Sabbath because it is muktzeh.

As explained in the notes on Halachah 21, one is not liable for trapping these creatures, because no real effort is required in doing so.

The Maggid Mishneh questions why the Rambam uses the term “is not liable,” which implies that it is forbidden to do so by Rabbinic decree. What prohibition is there in releasing an animal from a trap? He answers that perhaps the intent is that the person is liable for violating the Rabbinic prohibition that deems an animal as muktzeh. Note the Magen Avraham 316:11 which states that one may release an animal or a fowl from a trap, provided one does not touch them.

See Hilchot Sh’vitat Yom Tov 2:5, where the Rambam states that chickens and ducks are considered as within a person’s grasp. Note, however, the distinction between the different types of doves mentioned in that halachah and in this halachah. Because of that difference, the Maggid Mishneh considers the1rilention of doves in this halachah as a printing error. Mention of them is found, however, in most early manuscripts and printings, and other authorities justify their mention.

Rav Kapach states that this refers to non-kosher locusts. A person who catches kosher locusts is liable. The Mishnah Berurah 316:13, however, differs, and maintains that the Rambam does not hold one liable for trapping such species.

Since it is not customary to trap these species, even a person who traps them for a specific purpose is not held liable (Shulchan Aruch HaRav 316:4). There is, however, a Rabbinic prohibition involved. For that reason, one must even take precautions not to trap such creatures accidentally (Ramah, Orach Chayim 316:3).

I.e., not only is one not liable, but is permitted to do so.

Most commentaries explain this ruling according to the opinions that do not hold one liable for performing a הפוגל הכירצ הניאש .הכאלמ Although generally there would be a Rabbinic prohibition against such an act, in this instance no prohibition was enforced because of the danger involved.
This explanation is, however, untenable for the Rambam, for as explained in Chapter 1, Halachah 7, he follows Rabbi Yehudah’s ruling that holds one liable for performing a הכאלמ. הניאש הכירצ הפוגל
The Avnei Nezer (Likkutim 189) explains that this situation is different, because of the unique nature of the labor of trapping. The concept of trapping is relevant only when one traps an object of value. Therefore even Rabbi Yehudah frees one of liability when trapping an animal whose species is not usually trapped.
Similarly, in the instance at hand, since one has no concern for the object one is trapping, merely for one’s personal welfare, the entire concept of trapping does not apply. See also the notes on Halachah 17 of this chapter and Chapter 11, Halachah 4.