Shabbat belongs to Jews alone, as the Torah states: “For it is a sign between Me and you throughout the ages, that you may know that I the Lord have consecrated you” (Shemot 31:13). In addition, the Sages go so far as to say that “A non-Jew who observes Shabbat is liable for the death penalty” (San. 58b). In other words, if a non-Jew were to invent his own religion and establish a “Shabbat” for himself, during which he would refrain from engaging in melakha and in developing the world, he would be liable for death at the hands of heaven (see Rashi ad loc. and MT, Laws of Kings 10:9).
Although a non-Jew may do melakha on Shabbat, the Sages forbade a Jew to ask a non-Jew to do melakha for him on Shabbat. This includes even rabbinically prohibited activities. The Sages found support for this from the wording of the verse: “No melakha shall be done on them” (Shemot 12:16). The verse does not use the active “Do not do melakha,” but rather the passive “No melakha shall be done.” Thus we see that it is proper that no melakha is done for a Jew on Shabbat or Yom Tov. As the Midrash elaborates: “‘No melakha shall be done’ – neither by you, nor by your friend, nor by a non-Jew” (Mekhilta ad loc.).
If the melakha will be done with a Jew’s property, one may not ask a non-Jew to do a melakha even for the non-Jew’s benefit. For example, one may not tell a visiting non-Jew: “Turn on the light for yourself.” Similarly, one may not say to a non-Jew: “Cook my food for yourself.” However, if the meat belongs to the non-Jew, one may tell him to cook it for himself. Since the non-Jew is performing the melakha with his own possessions for his own benefit, the Sages did not forbid such speech (SA 307:21; MB ad loc. 73).
The Sages decreed that a Jew may not benefit from a melakha performed by a non-Jew for the Jew’s benefit. For example, if the lights in one’s home went out, and a non-Jewish neighbor came and turned the lights on, neither the Jews living in that home nor any other Jews may benefit from these lights, since they were turned on for a Jew on Shabbat (SA 276:1). If the melakha undertaken by the non-Jew is time-consuming, a Jew may not benefit from it immediately after Shabbat either. Rather, he must wait until enough time has passed so that the melakha could have been done after Shabbat. For example, if a non-Jew picked fruit or fished for a Jew on Shabbat, the fruit or fish may not be eaten after Shabbat until enough time has passed that they could have been picked or caught then (SA 325:5-6).
If the melakha performed by the non-Jew for the Jew is only prohibited rabbinically, then only the Jew for whom the melakha was performed may not benefit from it on Shabbat. Other Jews may benefit from the melakha even on Shabbat. Once Shabbat is over and enough time has passed so that the melakha could have been done after Shabbat, even the Jew for whom the melakha was performed may benefit from it (SA 325:8; MB ad loc. 41).
. Smag, Lo Ta’aseh §75, indicates that this Mekhilta means that the prohibition of asking a non-Jew to do melakha is a Torah law. Beit Yosef §244 quotes this. However, the overwhelming majority of poskim maintain that the prohibition is rabbinic, and the verse is not the law’s source but merely a support for it. This is stated by Rambam (MT 6:1); Ramban, Shemot 12:16; SAH 243:1; and SHT 243:7. There are two reasons presented for this prohibition. Rashi (Shabbat 153a) writes that if one requests that a non-Jew perform melakha for him, it is as if the non-Jew is acting as the Jew’s proxy. Alternatively, Rambam suggests that if one asks a non-Jew to do melakha for him, he will take Shabbat less seriously and thus may come to do melakha himself (MT 6:1). Either way, the rabbinic prohibition is an extension of the Torah’s command that servants rest on Shabbat, as explained above in 9:10.One may not even ask a non-Jew on Shabbat to do melakha for a Jew after Shabbat (MB 307:9) or ask him before Shabbat to do melakha for a Jew on Shabbat. However, one may hint to a non-Jew to do melakha in the future. For example, one may say: “Why didn’t you turn off the extra light in my house last Shabbat?” The non-Jew will realize that the Jew would like him to turn out the light the next Shabbat (SA 307:2).
. The prohibition on benefiting from melakha done by a non-Jew on Shabbat is explained in Shabbat 122a, while the need to wait after Shabbat is explained in Beitza 24b. According to Rashi and Ran, the reason for the first prohibition is so that one will not benefit from melakha done on Shabbat; while according to Tosafot and Ramban, it is so that a Jew will not desecrate Shabbat by asking a non-Jew to do melakha for him (MB 325:29). If the melakha is undertaken publicly so that everyone knows that it was done for a particular Jew, that Jew may never benefit from it (SA 325:14; MB ad loc. 73).