Pikuakh nefesh, save a life, is the principle of Jewish law that holds the preservation of human life above nearly every other mitzvah. It is for that reason an extremely important part of the halakha for Jews.
The Torah gives us, “You shall therefore keep my statutes and my ordinances, by doing which a man shall live: I am the Lord” Lev 18:5. The prophet Ezekiel also says, “I gave them my statutes and showed them my ordinances, by whose observance man shall live” Ezek 20:11. Jews should live by the Torah, not die by it.
How important is pikuakh nefesh? Mishna Sanhedrin 4:5 taught that the Torah was indivisible. As part of that integral observance, they taught that, “Whosoever preserves one life, it is accounted to him by Scripture as if he had preserved a whole world.”
In the life of Israel, in the life of the new Israel, pikuakh nefesh supersedes virtually every other mitzvah. Rabbi Yeshua confirmed it. “I came that they may have life, and have it abundantly” Jn 10:10.