민수기 1:3의 Halakhah

Rabbi Goren presents a general discussion of the classical distinction between obligatory wars, permissible wars and wars of defense. More noteworthy is his presentation of sources pertaining to the establishment of minimum and maximum ages with regard to the conscription of soldiers. The chief difficulty in establishing a minimum age is that although Rashi, in his commentary on the Pentateuch (Exod. 30:14 and Num. 1:3), states that warriors must be "twenty years old and upward," Rambam, in his Mishneh Torah, is silent with regard to any such provision. The question of a maximum age limit centers upon the proper textual reading of the Sifre, Numbers 197, which establishes an upper limit of either forty or sixty years of age, depending upon which of the variant readings is accepted as accurate. Another problem to be resolved is whether these limits pertain only to permissible wars (milḥemet reshut) or are applicable to obligatory wars (milḥemet ḥovah) as well.

This also might explain why Chazal do not criticize Yoav for not resisting David Hamelech’s order to count the nation (see Shmuel II ch.24). Rav Itamar Warhaftig (Techumin 15:153) suggests that Yoav assumed that David felt that it was permissible to do so, as there are certain situations where counting the nation is permitted (see, for example, Ramban to Shemot 30:12 and Bemidbar 1:3). Therefore, a military order that is unambiguously wrong, such as gratuitously harming a peaceful demonstrator who is not endangering anyone, should be disregarded. If, however, the Prime Minister orders Tzahal to do something that is halachically ambiguous, it seems that the order must be obeyed.

2. However, in a subsequent comment, Ramban contradicts his own earlier interpretation. In his commentary on Numbers 1:3 Ramban remarks, "To me it [appears] unlikely that David should not be careful with regard to that which Scripture states, 'that there be no plague among them when you number them.' If perhaps David did err why did Joab not do [the census by means of] shekels … so that he should not sin?" Ramban proceeds to explain that a census such as was undertaken by David is forbidden even when conducted by means of counting half-shekels since it was unnecessary and not designed to serve a valid need or "purpose" (zorekh). David's census, asserts Ramban, was not designed to serve a military purpose or any other national need. That census, he declares, was undertaken by David simply in order to "gladden his heart" by demonstrating that he reigned over a large populace. In support of this thesis Ramban cites Bemidbar Rabbah 2:17: