to avoid repeating the aveira accidentally. Pikuach nefesh For most aveirot (such as violating the restrictions of Shabbat), if one must commit the aveira to save or possibly save a human life that is believed to be in danger, they are required to do so, and such an act is not considered an aveira, but is rather the fulfillment of one of the greatest mitzvot. This is the situation, regardless of whether this is a one-time occurrence, or must take place on a regular, on-going basis. Pikuach nefesh applies to Jews and gentiles whose lives are in danger alike, but not to animals whose lives are in danger. But there are a few exceptions. The major aveirot which traditional sources indicate a person should let themselves be killed rather than transgress include the Chillul Hashem (such as idolatry), murder, and immoral sexual behavior (adultery, incest, and other forbidden sex acts). Biblical prohibitions derived from these aveirot are also prohibited, even when a life is in danger. See also aveira goreret aveira "one sin leads to another sin" (Sayings of the Fathers 4:2) References Jewish law and rituals Hebrew words and phrases in Jewish law