It is well-known that when a person’s life is in danger, Heaven forbid, on Shabbat, the day is to be treated as a weekday as far as that patient is concerned. Anything that is necessary to help a gravely-ill patient is allowed, including turning on or off lights, if this is necessary to help the patient recover. In fact, this fulfills the great Misva of saving lives. This Halacha is codified in the Shulhan Aruch (Orah Haim 278).
The question, however, arises, is it preferable in such a case to ask a non-Jew to perform the Melacha? It goes without saying that if a non-Jew is not immediately available, a Jew should perform the Melacha that is necessary to help the gravely-ill patient, and the treatment should not be delayed at all until a non-Jew is found. However, if a non-Jew is present and willing to help, would it be preferable to have him perform the necessary Melacha to avoid having a Jew perform the Melacha?
The Mishna Berura (Rav Yisrael Meir Kagan of Radin, 1839-1933), based on a ruling of the Rama (Rav Moshe Isserles of Cracow, 1525-1572) in Siman 328 (Se’if 12), writes that indeed, it is preferable to ask a non-Jew to perform the Melacha, provided that this would not cause any delay whatsoever in tending to the patient. However, this is not the opinion of the Shulhan Aruch (328:12), who writes that in a case of a threat to life, a Jewish adult should violate Shabbat to help the patient, even if a non-Jew or minor is present and available to help. Several Rishonim (such as the Tashbetz and the Rosh) explain that if a non-Jew or minor is asked to perform the Melacha, people might mistakenly conclude that this was done because rescuing a life does not override the Shabbat prohibitions. And if another life-threatening situation arises, these people would begin looking for a non-Jew, or a minor, thereby endangering the patient. This is the ruling accepted by Hacham Ovadia Yosef, in Hazon Ovadia (vol. 3, p. 283; listen to audio recording for precise citation), and by Rav Moshe Feinstein (Russia-New York, 1895-1986), in his Iggerot Moshe (5:28). Therefore, when a person’s life is in danger on Shabbat, a Jewish adult, and not a non-Jew or minor, should perform whichever Melachot are necessary to help the patient.
Summary: If somebody’s life is in danger on Shabbat, a Jewish adult, and not a non-Jew or minor, should perform whichever Melachot are necessary to help the patient. Even if a non-Jew or minor is present and willing to help, the Melachot should be done specifically by a Jew, lest people mistakenly conclude that rescuing lives does not override the Shabbat prohibitions.
