In I got It!
Thou Shall Guard …
A personal injury that results from disregard of the obligation to ‘Guard one’s life’, can ultimately be fatal. Not so much because of the severity of the injury itself, in as much as the divine judgment that he is subject to because of his carelessness.
This rule is derived from a story in the Gemara about the Angel of Death who took the soul of a woman who was not decreed to die, in place of the soul of another woman who had in fact been slated for death.
The story is brought in the Gemara Meseches Chagiga 5a, which describes a conversation between Rav Bibi bar Abaye and the Angel of Death. The Malach haMaves was on a mission to take the life of a woman without trial, and argued to the Tanna that the woman had taken a shovel in her hands after using her oven, and placed the shovel with glowing coals on her knees. She scorched herself, and since her mazal was then at a critically low point, he succeeded in taking her life.
In fact Chazal say – ‘The Satan only accuses at a time of danger’ (Bereishis Rabba 91:12). It follows that one who places himself in a situation of danger, brings a divine judgment on himself that the Malach haMaves can exploit in order to take him from this world before his time.
Halacha forbids a person from entering into a situation of danger, and obligates him to find every way possible to distance himself from it. If he does chance upon danger, he is commanded ‘And you shall guard your lives exceedingly’ (Devarim 4:15). Many halachos are derived from this commandment, such as the prohibition to light the Chanuka menorah at the entrance to one’s home at a time of danger (Shabbos 21). In many places we find that Chazal rule ‘chamira sakanta me’isura’ – ‘The danger is more severe than the actual prohibition’ (Chulin 10).