Conquering the Land of Israel
We have a general rule: “You shall live by them (the words of the Torah) and not die by them” (Yoma 85b). The Torah was given to Am Yisrael in order that the Jews live by it, not die by it. According to this rule, the well-known halakha was established that “pikuach nefesh (a life-threatening situation) nullifies the Shabbat.” That is to say, Shabbat is desecrated in order to save a life. For instance, although driving a car is forbidden on Shabbat, it is permitted, and even a mitzvah, to drive a dangerously-ill person to the hospital for emergency treatment. Furthermore, not only is the Shabbat desecrated for pikuach nefesh, so are all of the mitzvot. Therefore, if non-Jews were to order a Jew, under the threat of death, to do something that involved transgressing a commandment from the Torah, he should do it and not put his life in danger, except for three major transgressions: idol worship, illicit sexual relations, and murder. If someone said to him, “Kill your friend, or we’ll kill you,” he should be ready to be killed, rather than kill someone else. Also, if they told him to worship a certain idol, or else they would kill him, he must be ready to give up his life and not sin. This rule also applies to illicit sexual relations. For all other mitzvot, however, one should not sacrifice his life (Sanhedrin 74a).
All this concerns commandments incumbent upon the individual. However, pikuach nefesh does not apply to the mitzvah of settling the Land of Israel, which is a general mitzvah of Clal Yisrael. From the mere fact that the Torah commanded us to conquer the Land, we must be ready to endanger our lives, for there is no war without casualties, and the Torah does not expect us to rely on miracles. Rather, the mitzvah of conquering and settling the Land, which is incumbent on the Nation, requires complete miserut nefesh (self-sacrifice) (Minchat Chinuch 425, 604; Mishpat Kohen 143; Igrot Ra’ayah, Sect. 3, 944). This was the case in the days of Yehoshua and David, as well as during the establishment of the Second Temple; and later, at the time of the Maccabees and the Hasmonean Kingdom, and in the days of Rabbi Akiva and Bar Kochva.
The rule of “and you shall live by them” applies even to general mitzvot. However, with regard to the mitzvah of settling the Land of Israel, since the commandment also pertains to the general populace, the fate of the entire Israeli Nation – and not just individual soldiers – must be considered. Therefore, in a case where military defeat is highly possible, and, God forbid, we are likely to lose parts of the Land that we already possess, thereby threatening the life of the entire Nation, in such a situation, there is no mitzvah to go to war to conquer the Land. However, when there is a good possibility that we will be victorious, even though it is clear that a number of us will lose our lives, we are commanded to fight for the Land and at the very least, to defend the areas already in our possession.
I must mention here, that any nation that is not willing to fight with a spirit of self-sacrifice for its country exposes its sons and daughters to dangers from neighboring enemies. For any nation which cannot mobilize its sons to fight for its homeland, will, in the long run, be conquered. Therefore, the mitzvah to fight for the Land of Israel with a readiness for self-sacrifice corresponds to the universal understanding of war, where soldiers are called upon to fight for their countries, even though many may die.