Are you allowed to pet your dog on Shabbos?

To protect the spirit of Shabbat, the Sages...introduced the prohibition of muktzeh (as explained in the next chapter)...

(12) The Sages forbade the carrying of certain objects on the Sabbath in the same manner as [one carries] during the week. Why was this prohibition instituted? [Our Sages] said: If the prophets warned that the manner in which a person walks on the Sabbath should not resemble the manner in which he walks during the week, and similarly, one's conversation on the Sabbath should not resemble one's conversation during the week...surely the manner in which one carries on the Sabbath should not resemble the manner in which one carries during the week. In this manner, no one will regard [the Sabbath] as an ordinary weekday...and...have negated the motivating principle for the Torah's commandment [Deuteronomy 5:14], "In order that you rest."

(13) Furthermore, when one searches for and carries articles that are used for a forbidden activity, it is possible that one will use them and thus be motivated to perform a [forbidden] labor.

[Another reason for this prohibition is] that there are some people who are not craftsmen and are always idle...Were they to be allowed to walk, talk, and carry as they do during the week, the result would be that their cessation of activity on [the Sabbath] would not be discernible. For this reason, [our Sages instituted] refraining from such activities, for the cessation of such activities is universally applicable...

...moving...is due to the prohibition of carrying out...

(1) Muktzeh / The Basis of the Prohibition

(2) The Sages prohibited moving things that are not fitting for Shabbat and that one puts out of his mind (maktzeh mi-da’ato). There are two fundamental reasons for this prohibition:

1) to preserve the atmosphere of Shabbat as a day of holiness and rest. The idea of rest applies to one’s hands as well; they should not move objects or be involved with activities that are not connected to Shabbat;

2) to set up a safeguard so that one will not come to do melakha on Shabbat. We will begin by explaining the first reason.

(3) In addition to the melakhot that are prohibited on Shabbat, the Torah commands us to rest and relax on Shabbat, as it states: “but on the seventh day you shall cease, so that your ox and your donkey may rest, and the son of your maidservant and the stranger may be refreshed” (Shemot 23:12). Similarly, we read: “Six days shall work be done, but on the seventh day there shall be a Shabbat of complete rest, holy to the Lord” (Shemot 31:15). In order to fulfill the Torah commandment to rest and relax on Shabbat, the Sages established several ordinances meant to protect the spirit of Shabbat as a day of sanctity and rest. One of them is the prohibition of muktzeh. If moving items unnecessary for Shabbat were permitted, people might well spend all of Shabbat cleaning and arranging their homes and belongings, thus negating the mitzva to rest. Additionally, the prophets instructed the people that the atmosphere of Shabbat should be different from that of the weekday – one should walk and talk differently. Following this line of thought, the Sages decreed that people should not handle objects and implements on Shabbat in the same way as during the week. This way Shabbat is truly felt by all, including those whose weekday activities do not normally involve any forbidden melakhot. We see that the prohibition of muktzeh is rooted in the words of the Torah and the prophets, while its precise parameters and details are rabbinic (AHS 308:4-5; above, 22:1).

(4) As we said, the second reason is so that one will not end up doing melakha on Shabbat. As with all mitzvot, the Sages instituted safeguards in order to distance people from sin. The prohibition of muktzeh makes it less likely that people will carry objects in the public domain or use muktzeh items to perform melakha (Rambam and Raavad, MT 24:12-13).

(5) The prohibition of muktzeh synchronizes the mind and the hands. Any item that one knows is not fit for use on Shabbat will not be touched by his hands either.

(1) Muktzeh / Principles of Muktzeh

...There are several types of muktzeh:

1) Muktzeh maḥmat gufo (inherently muktzeh) – items that are not fitting for any use on Shabbat, such as rocks, trees, sand, animals, and inedible food...

2) Muktzeh maḥmat ḥesron kis (muktzeh because of monetary loss) – valuable objects that one takes care not to handle except for their sole designated use, out of concern that they will be ruined...

3) Basis le-davar ha-asur (a base for a forbidden object) – refers to a case where one places a muktzeh item on an object that is not itself muktzeh; since he intends for it to remain there on Shabbat, he puts the “base” out of his mind as well, and it too becomes muktzeh...

4) Kelim she-melakhtam le-isur (implements whose usage is forbidden) – have a special status. Since they are designed to perform forbidden activities, one puts them out of his mind. On the other hand, sometimes they are used for permitted purposes. Therefore, one may not move them for their own sake (e.g., to protect them, le-tzorekh atzmam), but one may move them to use them permissibly (le-tzorekh gufam) or because one needs the space they occupy (le-tzorekh mekomam)...

(3) If a muktzeh item is painfully unpleasant, like a chamber pot (graf shel re’i), the Sages permitted removing it (section 12 below).

(4) The prohibition is to move a muktzeh object manually, but one may touch a muktzeh item without moving it. Therefore, one may spread a cover over a computer, telephone, or other muktzeh items on Shabbat. One may also move muktzeh “from the side” (min ha-tzad). For example, if one needs to pick up an object or food, and in so doing a muktzeh item that is next to the object or food will be moved indirectly, as long as he does not touch the muktzeh item with his hands, it is not prohibited. However, if the muktzeh item needs to be moved for its own protection, one may not move it even min ha-tzad. As long as he is using his hands, even if they have no direct contact with the muktzeh item (for example, if he is using a broom), it is prohibited. However, one may use any other part of the body (be-gufo); for example, one may move an object that is muktzeh using his foot or elbow (section 14 below).

(5) Sometimes it is unclear whether or not a particular item is muktzeh because we lack facts about the situation. For example, if one found fruit under a tree and it is uncertain whether they fell before Shabbat (and are permitted) or on Shabbat (and are muktzeh), we are stringent and consider it muktzeh (Beitza 24b; SA 325:5). In contrast, if there is a halakhic disagreement about whether an item is muktzeh, the law follows the lenient position (Beit Yosef 279:4; SHT 309:24).

39. It is forbidden to handle animals and fowl...

40. It is permitted to assist animals and fowl to walk in the yard, namely one holds its neck and side and makes it walk, if the animal requires it. This is as long as one will not lift it in such a way that its feet will be off the ground, because it is Muktze and forbidden to be carried....

...A hen that fled that one seeks to retrieve, one may push it even with his hands until it reenters the house. One may help calves and foals to walk, and likewise a woman may help her son to walk. Rabbi Yehuda said: When is it permitted? When her son picks one foot up and puts one foot down by himself. However, if her son were dragging both his feet, it would be prohibited because it would be like carrying him in the public domain.

It is forbidden to negate the possibility of using a utensil, since this is comparable to destroying [it]. What is implied? A person should not place a receptacle below a lamp on the Sabbath to receive any oil that drips. For the oil in the lamp is forbidden to be carried, and when it falls into the receptacle it will cause the receptacle that had been permitted to become forbidden. The same applies in all analogous situations...

[The following rules apply when] an animal falls into a cistern or into a water conduit [from which it cannot ascend on its own]: If one can supply it with its needs while it is there, one should do so until Saturday night. If not, one may bring cushions and blankets and place them beneath it. If this [enables the animal] to ascend, there is no difficulty. Although one is nullifying the possibility of using a utensil - for one is throwing it into a cistern [filled with] water - [our Sages did] not institute a decree [in this instance], because of the suffering [the] animal endures. It is forbidden to lift the animal up by hand...

An animal that fell into a water canal, if the waters are deep and therefore the animal cannot be provided for in its present location, one may bring pillows and quilts and place them beneath it because of ‘tza’ar ba’alei chayim’, [agony to animals – we are commanded to not to hurt them and to look after their well-being] even though it is Mevatel Keli Me’hechano...

...The measure that determines liability for carrying out a live kosher locust is any amount. For carrying out a dead kosher locust, which is edible, it is the same as any other food, a fig-bulk...Rabbi Yehuda says: Even one who carries out a live non-kosher locust is liable for carrying out any amount, because people store locusts for a child who wants to play with it.

As we will see later on (23:5), anything that has no practical use on Shabbat is muktzeh and may not be carried. Animals are included in this category and thus may not be carried on Shabbat. If, in order to prevent them from being hurt, it is necessary to move them, the Sages permitted pulling them but not picking them up (SA 308:39-40). At first glance, this would seem to pertain to house pets like cats and dogs, and indeed, this is the position of Yalkut Yosef (vol. 2, p. 383) and Orḥot Shabbat (19:124). However, it seems more reasonable to assume that muktzeh pertains only to animals with which one does not normally play. Pets whose owners play with them and pick them up all week long would not be muktzeh, and their owners may thus touch them and pick them up on Shabbat. Similarly, seeing-eye dogs are not muktzeh (Igrot Moshe, OḤ 5:22:21; Shulḥan Shlomo 308:74). Although some are stringent, muktzeh is a rabbinic prohibition so the halakha follows those who are lenient. A fish that jumped out of an aquarium and will presumably stay alive if it is returned may be put back even though it is muktzeh. This is because, when necessary, and when there is no other solution, one may move a muktzeh object to prevent tza’ar ba’alei ḥayim. Even though some are stringent in this case, one may rely on the lenient approach (See SA 305:19; MB ad loc. 70; SSK 27:28). If a fish in an aquarium dies, and it is possible that if it is left in the aquarium other fish will catch whatever terminal disease it had, then even though the dead fish is muktzeh, it may be removed from the tank to save the remaining fish. If there is a dog or cat in the vicinity, the fish should be fed to them (see SSK 27:29).