Sanhedrin Daf 74 סַנהֶדרִין דַף 74

Rebbe Yonasan ben Shaul said that if a רודף was pursuing someone to kill him, ויכול להצילו באחד מאבריו – and one was able to save [the potential victim] by disabling one of [the רודף’s] limbs, ולא הציל – and he did not save him that way, but killed the pursuer, נהרג עליו – [the rescuer himself] is killed for it, since it was not necessary to save the victim. The passuk says: וכי ינצו אנשים – if men shall fight, and they inadvertently strike a pregnant woman and she miscarries, etc. Rebbe Elazar says it is discussing מצות שבמיתה – a fight to the death (where they intended to kill each other), since if there is a fatality, the killer is executed, which is only possible if they intended to kill. Still, if there is no fatality, he must pay for the loss of the fetus. Since a רודף may be killed to stop him, he should be exempt from any monetary payments!? Rather, the passuk’s case must be שיכול להציל באחד מאבריו – that one was able to save [the victim] by disabling one of [the רודף’s] limbs, and proves that the רודף may not be killed in such a case.

Rebbe Yochanan reported that it was voted and decided that regarding all aveiros, if one is told, “Trangress this aveirah or else we will kill you,” then יעבור ואל יהרג – he should transgress it and not be killed, except for avodah zarah, גילוי עריות, and murder. Rebbe Yishmael holds one should even serve avodah zarah rather than be killed, but we rule like Rebbe Eliezer, who darshens the commandment to love Hashem "בכל נפשך ובכל מאדך" – with all your soul and all your resources, to teach: אם יש לך אדם שגופו חביב עליו מממונו – if you have a person whose life is more precious to him than his money, he is commanded to sacrifice even “כל נפשך,” i.e., his life. If one’s money is more precious to him than his life, the Torah says to sacrifice even “your money.” The requirement to be killed to avoid גילוי עריות is derived from a hekesh with murder, which is known through logic: a governor once ordered someone to kill a Jew or else be killed, and Rabbah told him to allow himself to be killed rather than murder, because מי יימר דדמא דידך סומק טפי – who says that your blood is redder than his? דילמא דמא דהוא גברא סומק טפי – Perhaps the blood of that man is redder than yours!

Rebbe Yochanan said that בשעת גזירת המלכות – during a time of governmental decrees against Judaism, one must sacrifice his life to avoid transgressing even מצוה קלה – a minor mitzvah. Rebbe Yochanan said the same for any aveirah transgressed בפרהסיא – in public (i.e., before ten Jews). A "מצוה קלה" includes even changing ערקתא דמסאנא – his shoelaces (where the Jewish practice differs for modesty purposes).

The Gemara asks: והא אסתר פרהסיא הואי – but Esther’s living with King Achashveirosh was public knowledge!? Why were such relations permitted? Abaye answers that Esther was קרקע עולם – like the ground of the earth, i.e., completely passive in relations, and was not required to sacrifice her life. Rava answers: הנאת עצמן שאני – gentiles’ demands which are for their own pleasure (such as Achashveirosh) are different and permitted even in public. This explains the permit to contribute brass utensils for heating in idolatrous temples. Similarly, Rava ruled that if a gentile instructed a Jew to cut אספסתא on Shabbos to feed his animals, or be killed for refusing, he should obey, but if he told him to throw the אספתא in the river, he must refuse, since the gentile’s goal is the transgression.