 The self-endangerment rule is grounded partly on a Biblical verse that is read as an injunction to watch one's health - "ונשמרתם מאד, לנפשתיכם" [Vi'nish'martem Me'od Li'naf'sho'tey'chem] "And you shall watch yourselves very well ..." Similarly, rabbinic rules against damaging others are traced back to Biblical and Talmudic laws.Famous Ashkenazi Haredi rabbis have called on people not to smoke and called smoking an 'evil habit.