http://www.askmoses.com/en/article/271,2230417/From-where-does-the-saying-Save-a-life-save-a-whole-world-originate.html Question:
Where does the saying, "save a life, save a whole world" come from? I'm not even sure it's Jewish. Thanks, Milty N.
Answer:
The Talmud asks why the human race was created as a single human being, as opposed to creating many people at once (like the animals which were created en masse1 )?
This teaches us that just as Adam was created in the beginning, and he was the entire human population of the world, likewise we need to look at each individual as if he/she were the entire population of the world. Therefore, when you save one life it is as if you saved the entire world.
Talmud, Sanhedrin 37a states:
"FOR THIS REASON WAS MAN CREATED ALONE, TO TEACH THEE THAT WHOSOEVER DESTROYS A SINGLE SOUL... SCRIPTURE IMPUTES [GUILT] TO HIM AS THOUGH HE HAD DESTROYED A COMPLETE WORLD; AND WHOSOEVER PRESERVES A SINGLE SOUL..., SCRIPTURE ASCRIBES [MERIT] TO HIM AS THOUGH HE HAD PRESERVED A COMPLETE WORLD."
Footnotes
* 1. Genesis 1:24-26