Qitzur Shulchan Arukh – 184:8
Someone who sees his friend in trouble, heaven forbid, and he could help [the person with a problem] himself or hire others to save him, he is obligated to put in the effort, and hire, and save him. He can then return and collect [expenses] from him if he has it. If [the person in trouble] doesn’t have it, you can not in any case hold back because of this — he should save him with his own money. And if he holds back, he violates “do not stand by on your friend’s blood” (Vayiqra 19:16).
Similarly, if he heard from some wicked people that they plan to do some evil to his friend, or they set [literally: bury] a trap for him and he doesn’t reveal that he heard to let him [the potential victim] know, or he could appease them with money on behalf of his friend and they would remove [the idea] that is in their hearts and he doesn’t appease them, and everything derived along these ideas, he violates “do not stand by on your friend’s blood”.
“And whomever saves one soul of Israel, it is as thought he saved the full world.”
(And see Yoreh Dei’ah siman 158.)
A note about the closing quote. It comes in numerous variants and it is unclear that the version in the Qitzur was the original. Or that the original limits the saying to souls of Israel. The following discussion was posted by Amitai Halevi on scj on 4-Nov-1994:
The source for this saying is in the Mishnah, Sanhedrin 4:5. It appears in several versions:
1. In the standard edition of the Mishnayot, the wording is: “Whoever destroys the life of a single human being [nefesh a`hat mi-bnei adam] … it is as if he had destroyed an entire world; and whoever preserves
the life of a single human being … it is as if he had preserved an entire world”.
2. In the Talmud Bavli, where this mishnah appears on Sanhedrin 37a, the wording is the same, except for the substitution of “life of a single Jew” [nefesh a`hat \mi-yisrael] for “life of a single human being”.
3. In the Talmud Jerushalmi, Mishnah 5 is divided into subsections (Halakhot). In my edition the saying appears in Halakhot 12-13. Others divide Mishnah 5 differently: e.g. MTR locates it in Halakhah 9. It reads “destroys a single life” [ma’abed nefesh a`hat] and “preserves a single life” [meqayem nefesh a`hat]. There is no specific mention of either “human being” or “Jew”, though the former is clearly implied.
The question is: Which is the original version? Was the limitation to Jewish lives there to begin with, and then taken out as a result of Church censorship? This is suggested in the book of corrigenda, Hesronot Ha-shas. Alternatively, was the universal formulation the original one, and the limitation to Jewish lives introduced into it at some later date, perhaps in a period when particularly severe persecution of Jews generated a justified feeling of xenophobia?
The answer would seem to be obvious from the context, which is the same in all three versions. The citation is preceded by the words: “This is why Adam was created alone. It is to teach us that …”. A bit father down it reads: “When a man mints a number of coins from a single die, they are all identical; but the King of the kings of kings, the Holy One blessed be He, minted every human being from the die of the primal Adam, and not one of them is like any other”.
Evidently, if the original had referred to the preservation of Jewish lives alone, the reference would have been to Abraham at the earliest. The repeated reference to Adam, progenitor of all mankind, makes it clear that the original must have referred to the preservation of human life in general.
This is apparently how the Rishonim (medieval commentators) understood it as well. Rambam adopts the Yerushalmi version, (3.) slightly altered, in Hilkhot Sanhedrin 12:3, but also cites the Bavli version (2. above) briefly in Hilkhot Rotzea`h 1:6. Hameiri too bases his commentary on the Yerushalmi version, illustrating “the destruction of a whole world” by pointing out that Cain’s murder of Abel eliminated all of his victim’s descendants at one fell swoop. Abel, like Adam was not Jewish; he was not even the ancestor of Jews.
The humanistic version was not universally accepted by the A`haronim (later commentators). MaHaRSh”A, for example, in Hidushei Agadot on Sanh.37a, stays with Version 2, and explains at some length why it is only important to save Jewish lives, even though the Mishnah bases the dictum on Adam’s being the father of all mankind. I would be interested in learning what present-day Orthodox Judaism regards as the authentic reading.
(Posted and mailed)