Big 3 Cardinal Sins
I am intrigued by which of the "Big 3 mitzvahs" a Jew is expected to give his life for rather than transgress. What exactly are they, and where do they come from?
The Aish Rabbi Replies:
This is a serious subject with lots of material written on it. We can't possibly learn all the details, but let's try to get a general idea.
Maimonides writes that if a person were to say to a Jew "Violate one of the commandments or I will kill you," the Jew should violate the commandment and not be killed, since that the Torah says "You shall observe My decrees and My laws, so that you shall live by them." The inference from the words "live by them" is that you shall not "die by them!" This however does not apply to three mitzvahs: 1) murder 2) forbidden sexual relations and 3) worship of other gods. (Maimonides - Foundations of the Torah 5:2)
Imagine the case: Mike says to Dave: "Either you kill that person, or I will kill you." The law is that Dave must allow himself to be killed rather than kill the other person. The reason is logical, in the language of the Talmud: "What makes you think your blood is redder than his? Perhaps his blood is redder!" Or in other words, "How can you judge between your life and his? Perhaps he is worthier than you!" Since it is impossible to know who is the "better Jew," one has to let the circumstances play out without killing the other person. (Yoma 82b)
This logic applies even if Mike were to say to the inhabitants of a Jewish town, "Give me one Jew to kill, or if you don't, I will kill all of you." Since it is impossible to decide whose blood is the "least red," the town must not give anyone to Butch to be killed, and they must all allow themselves to be killed. (Maimonides - Yesodei HaTorah 5:5)
FORBIDDEN SEXUAL RELATIONS
The reason why someone must allow himself to be killed rather than be involved in forbidden sexual relations, is because the Torah compares rape to murder. (Deuteronomy 22:26, Talmud - Yoma 82a)
The reason why one must allow himself to be killed rather than worship other gods comes from a verse in the Shema: "You shall love your God with all your heart, WITH ALL YOUR SOUL, and with all your possessions" (Deuteronomy 6:5). In other words, you should love God so much that you're willing to give up your life to serve him (Talmud - Yoma 82a).
The reason why loving God with all your soul specifically applies to the worship of other gods is because the belief that "God is One," the Creator and Controller of everything, is the basis for all of Judaism. The worship of other gods is a denial of this basic tenant.