The Shulhan Aruch (OC 307) rules that the prohibition of Amira L’Akum-instructing a non-Jew to perform a Melacha on Shabbat, applies also to "Shvut D’shvut"-instructing a non-Jew to perform a Rabbinic transgression. That is, instructing a non-Jew to perform any violation of Shabbat, even a Melacha forbidden by the Torah, is only prohibited M’Drabanan-by Rabbinic law. If one instructs him to do an act, which even if done by a Jew, is only prohibited M’Drabanan, this is called a "Shvut D’shvut, and it is prohibited. However, the Shulhan Aruch rules that there are several extenuating circumstances in which "Shvut D’shvut" is permitted, including for the sake of performing a Misva, in a case of major financial loss or for the sake of a person who is sick.
When learning Halacha, it is critical to first grasp the underlying general principles before studying numerous specific applications. People mistakenly think that any "Shvut D’shvut" is permitted, and they sometimes extend the definition of a Misva to questionable cases. It should be clear: This leniency only applies for the sake of performing a bona fide Misva. Moreover, people sometimes mistakenly think that the act they want the non-Jew to perform is only M’Drabanan. For example, someone wants to ask his non-Jewish housekeeper to turn on a light to enable him to learn Torah, mistakenly thinking that this constitutes a "Shvut D’shvut." This is a mistake since most Poskim rule that turning on a light on Shabbat is a Melacha D’Oraita-a Torah Prohibition.
The question arises whether a Shvut D’shvut for a Misva is permitted, even in a case where the non-Jew’s act entails violating more than one Rabbinic transgression. The Shulhan Aruch actually presents such a case, in the context of Hilchot Shofar. The background for his ruling is:
1. Even though blowing the Shofar on Rosh Hashanah is a Torah Misva, The Rabbis prohibited doing so when Rosh Hashanah falls on Shabbat.
2. On such a Rosh Hashanah, The Peri Hadash (Rav Hizkiya Da Silva, 1656-1695) deems the Shofar to be "Mukse Machamat Gufo"-the most stringent form of Muksa. Since it has absolutely no use on Shabbat, it is analogous to a stone.
3. It is prohibited for a Jew to violate even a Rabbinic transgression on Rosh Hashanah in order to gain access to a Shofar.
In this light, Maran rules that in a year when the first day of Rosh Hashanah is on Shabbat, and the Shamash of the Bet Knesset hid the Shofar in a treetop before Shabbat, it is permitted to instruct a non-Jew to bring the Shofar on Shabbat, in order to blow it the next day, Sunday, the second day of Rosh Hashanah. Of course, the basis of this ruling is "Shvut D’shvut", asking a non-Jew to perform a Rabbinic transgression for the sake of the Misva of Shofar. However, when analyzing the case, it becomes apparent that bringing that shofar entails a simultaneous violation of three different Rabbinic prohibitions.
1. On Shabbat, handling the shofar is a violation of Mukse.
2. It is Rabbinically prohibited to use or climb a tree on Shabbat or Hag.
3. Sending the non-Jew on Shabbat constitutes a violation of "Hachana," preparing for the next day, since the Shofar won’t be used until Sunday.
This ruling pertains to a case in which the non-Jew would not be available on Sunday, and therefore the problem of Mukse and Hachana could not be avoided.
Based on this ruling, the Poskim derive a general principle by which Shvut D’shvut for a Misva is permitted even if the Non-Jew’s act entails violating numerous Rabbinic transgressions.
One may instruct a non-Jew to perform a Rabbinic transgression on Shabbat for the sake of a Misva, even if the act entails violating numerous transgressions.