While it is permitted to perform any labor necessary to save lives, it is important to remember, when deciding how to act, that on the other side of the scale is the sanctity of Shabbat. Therefore, permission to desecrate Shabbat applies only to actions that are necessary to save lives; it is not a blanket permission to perform any action. It is also imperative to refrain from knowingly putting oneself in any life-threatening situation on Shabbat.

The permission to desecrate Shabbat in a case of pikuah nefesh includes situations where it is uncertain whether human life is actually in danger or if a particular treatment will indeed save the person’s life; even possible pikuah nefesh overrides Shabbat. Furthermore, even if it is clear that the person’s life will not be spared in the long run, but there is reason to assume or hope that the action will extend his life, even for a very brief period of time, it is permitted to desecrate Shabbat for his sake.

If the person whose life is in danger refuses to allow others to desecrate Shabbat for him, he should be persuaded that this is permitted and even a mitzva.

Further reading: For more on the sanctity of life and pikuah nefesh, see A Concise Guide to the Sages, pp. 6, 150.

The following are examples of patients defined as someone whose life is in danger and for whom it is permitted to desecrate Shabbat: one whose doctor has determined that his life is in danger; a sick person who believes that his own life is in danger, even if the doctor thinks otherwise; and one who has a high fever for an unknown reason and generally feels unwell. It is permitted to desecrate Shabbat even for the sake of one who is currently feeling well but whose condition might deteriorate into a life-threatening state if he does not receive treatment on Shabbat.

A woman in childbirth is defined as being in a life-threatening situation from the beginning of the birth process until the conclusion of the seventh day after the baby is born. If a complication develops during or after birth, she may be considered in danger even longer.

When one needs to speak on the phone to call for help or to receive medical guidance, it is not necessary to limit the scope of the discussion of the medical situation in order to minimize the Shabbat violation; rather, one may conduct the conversation about the medical matter unhurriedly, for as long as the situation requires.

At a time of need, it is permitted to transport a person in a car for emergency treatment, and likewise one may drive to bring him medicines or lifesaving equipment. Ideally, it is advisable to travel to the nearest medical center. Nevertheless, if a medical center that is farther away can give better treatment, or even if the patient believes that to be the case and therefore wants to travel to a more distant medical center, it is permitted to drive there. If one does not know the way there, he may turn on a navigation device.

If there is certainty or high probability that during Shabbat one will have to drive a car, e.g., in the case of a woman in the final stages of her pregnancy, one should perform certain actions before Shabbat in order to minimize the desecration of Shabbat:

(1) Disable the car alarm.

(2) Disable the automatic light that turns on upon opening the doors. If for some reason this was not done, then it is best when entering the car, before closing the doors, to switch the light to the permanently on state, so that future closing and opening of the doors will not cause the light to turn on and off again.

(3) Before Shabbat, one should remove from the vehicle any items that will not be needed on Shabbat. If this was not done before Shabbat, one should remove any heavy items on Shabbat itself before departing, even if those items are classified as muktze.

When traveling on Shabbat to save a life, one must ensure that the trip and all other prohibited actions be performed solely for the sake of the person whose life is in danger. Nevertheless, the drive itself must be conducted carefully while avoiding speeding and in accordance with all the traffic laws, just like on a weekday, to make sure not to endanger additional human lives.