Pikuach nefesh (Hebrew: פיקוח נפש), which means "saving a soul" or "saving a life," is the principle in Halakha (Jewish law) that the preservation of human life overrides virtually any other religious rule of Judaism. In the event that a person is in critical danger, most mitzvot become inapplicable if they would hinder the ability to save oneself or someone else.[1] However, there are certain exceptions; some rules and commandments may not be broken under any circumstances and thus may require an act of self-sacrifice.
For example, as noted in Chapter 2, the principle of pikuakh nefesh, of saving a life, takes precedence over virtually all other mitzvot.