Halakhah sobre I Samuel 25:28

The question of whether a preemptive war is included in the category of milḥemet mizvah or milḥemet reshut is crucial with regard to yet another aspect of Halakhah. The Mishnah, Sanhedrin 2a, stipulates that a discretionary war may be undertaken only upon the acquiescence of the Great Sanhedrin composed of seventy-one members. A subsequent Mishnah, Sanhedrin 20a, implies that a discretionary war may be undertaken only by a monarch. Thus, a discretionary war cannot be justified unless undertaken by the king⁴Ramban, addenda to Rambam’s Sefer ha-Miẓvot, miẓvot aseh, no. 4, states that the requirement that war be undertaken only by a king must be understood as including not only a monarch but any sovereign authority. Thus he states that war may be undertaken by “a king, a judge or whosoever exercises jurisdiction over the people.” For sources discussing Rambam’s possible disagreement regarding this point, see Contemporary Halakhic Problems, II, 207, note 27. with the permission of the Great Sanhedrin.⁵Rabbi Judah Gershuni, Torah she-be-‘al Peh, XIII (5731), 150f., advances the thesis that approval of the Sanhedrin is required only if the monarch finds it necessary to compel the populace to go to war and to conscript soldiers against their will, but that when the nation voluntarily agrees to go to battle approval of the Sanhedrin is not required. A similar view is advanced by Einayim la-Mishpat, Sanhedrin 16a. This view is supported by the comments of Me’iri, Sanhedrin 16a, who remarks that approval of the Sanhedrin is required in order to compel the populace to go out to battle. See also R. Abraham I. Kook, Mishpat Kohen, no. 145, and R. Saul Israeli, Amud ha-Yemini, no. 14 and no. 16, chap. 5, secs. 6-7. Cf., Amud ha-Yemini, no. 16, chap. 5, sec. 24. Moreover, in the context of a discussion of discretionary war, the Gemara, Berakhot 3b and Sanhedrin 16a, declares that the king may not undertake military action other than upon the approval of the urim ve-tumim.⁶Upon the twelve precious stones of the urim ve-tumim were engraved the names of the twelve tribes of Israel. In response to a specific query, various letters became illuminated. By means of the Divine Spirit the High Priest was enabled to combine the letters in order to discern the intended response.
Since no discretionary war could be undertaken other than upon approval of the urim ve-tumim, even discretionary war must be deemed to be undertaken with explicit divine approval and, conversely, no war could be undertaken other than with such divine sanction. Thus Abigail addresses King David and declares, “… for the Lord will certainly make a sure house for my lord because my lord fights the battles of the Lord” (I Samuel 25:28). Rambam, Hilkhot Melakhim 7:15, cites this verse and applies it to discretionary wars in stating:
Moreover, many ritual prohibitions are suspended even when discretionary wars are fought. Thus, once a discretionary war has been undertaken, it is permissible to wage such war on the Sabbath and combatants are permitted to partake of forbidden foods. The woman of “beautiful countenance” described in Deuteronomy 20:11 is permitted only to combatants engaged in discretionary wars but not to those engaged in commanded wars. It is thus clearly evident that even discretionary wars, when undertaken in accordance with the prescriptions of Halakhah, must be understood as undertaken by virtue of divine mandate. See Hilkhot Medinah, II, sha’ar 4, chapter 1, sec. 6. Indeed, Mekom Shmu’el, no. 8, suggests that the term “reshut” should be understood not as “permitted” or “discretionary” but as “licensed” or “sanctioned” in the sense that such war requires reshut Bet Din, i.e., sanction of the Sanhedrin, as distinct from wars that are obligatory by reason of explicit scriptural mandate. Although in Hilkhot Melakhim Rambam fails to mention consultation of the urim ve-tumim as a necessary precondition,⁷Cf., R. Yechiel Michael Epstein, Arukh ha-Shulḥan he-Atid, Hilkhot Mela-khim 74:7, who suggests that, even with regard to discretionary wars, consultation of the urim ve-tumim, although biblically mandated, is “perhaps” not a necessary condition of war. Although consultation of the urim ve-tumim constitutes a miẓvah and is required by virtue of biblical command, failure to engage in prior consultation, contends Arukh ha-Shulḥan he-Atid, does not affect the legitimacy of the war itself. See also, Le-Or ha-Halakhah, p. 12, and cf., Einayim la-Mishpat, Sanhedrin 16a. nevertheless, in the introduction to his Sefer ha-Mizvot, shoresh 14, Rambam does state that a High Priest is required for the undertaking of war; i.e., the king and the Sanhedrin may not undertake military action other than upon acquiescence of the urim ve-tumim which is attached to the breast-plate worn by the High Priest. Hence, absent a High Priest⁸See, however, Rambam’s reference to the function of the urim ve-tumim in Hilkhot Klei ha-Mikdash 10:11. who can consult the urim ve-tumim, offensive war in conformity with the stipulations of Jewish law is impossible. Ramban, in his addenda to Rambam's Sefer ha-Mizvot, mizvot lo ta'aseh, no. 17, declares that the requirement for consultation and approval of the urim ve-tumim is not limited to discretionary wars but applies with equal force to obligatory wars as well.⁹Rashi, in his commentary on the verse “and he shall stand before Eleazar the priest, who shall inquire for him by the decree of the Urim before the Lord” (Numbers 27:21), remarks that “even Joshua” was required to consult the urim ve-tumim “when he had need to go out to battle.” Since the wars of Joshua were all commanded wars, i.e., for the conquest of the territory inhabited by the Seven Nations, it must be inferred that Rashi agrees with Rambam in maintaining that consultation of the urim ve-tumim was necessary even in conjunction with commanded wars. See R. Judah Gershuni, Mishpat ha-Melukhah, Hilkhot Melak-him 5:2.
For a discussion of whether war against Amalek requires consultation of the urim ve-tumim, see R. Judah Gershuni, Torah she-be-‘al Peh, XIII (5731); cf., Contemporary Halakhic Problems, I, 16-18.

The laws of the commandment - for example, that which they, may their memory be blessed, said (Mishneh Torah, Laws of Kings and Wars 7:15) that a man not think at the time of war about his wife, nor his children nor his money, but rather he clear his [mind] from everything, to [focus on] the war. And he should further think that all the blood of Israel is dependent upon him, and [so] if he is afraid and 'he pulls back his right [hand],' it is as if he spilled the blood of all of them - and like the matter that is written (Deuteronomy 20:8), "and that the heart of his brothers not melt like his heart." And it is explicit in the words of the tradition, "Cursed be he who makes the Lord’s work a fraud; cursed be he who withholds his sword from blood" (Jeremiah 48:10). And [also] that which they, may their memory be blessed, said (Mishneh Torah, Laws of Kings and Wars 7:15) that anyone who fights with all of his heart and intention to sanctify God is assured that he will not find injury; and it will be a merit for him and his children, that his house will be established in Israel, and he will merit life in the world to come. And [it is] like the matter that is written (I Samuel 25:28), "for the Lord will surely make a faithful house for my master, since my master fights the wars of the Lord, etc." And the rest of the details of the commandment are in the eighth chapter of Sotah (see Mishneh Torah, Laws of Kings and Wars 6).