Halakhah zu Jehoschua 1:18

In accepting Joshua's charge to perform their military duties, the tribes of Reuben and Gad declared, "Whosoever shall rebel against your command and shall not hearken unto your word in all that you shall command him shall be put to death; only be strong and of good courage" (Joshua 1:18). R. Naphtali Zevi Judah Berlin, Ha'amek She'elah, She'ilta 142:9, observes that Joshua enjoyed the status of a judge, but not of a king. Hence, he queries, on what grounds was he empowered to punish disobedience with the death penalty? Despite the comments of the Gemara, Sanhedrin 49a, which appear to define the infraction as indeed constituting lèse majesté, Ha'amek She'elah declares that the answer is to be found in the final phrase of the verse, "be strong and of good courage." Although not a monarch, Joshua was the military commander about to embark upon a military campaign for the conquest of the Promised Land. A military leader must be courageous and confident. Those qualities depend, in part, upon a sense of authority and assurance that orders will be carried out without demur. Disobedience and breach of discipline, even if they do not directly affect military operations, are bound to have a demoralizing effect upon the leader responsible for waging war and will diminish his courage and determination. Any challenge to his authority is likely to weaken his self-confidence. That, in turn, would have a disastrous effect upon the course of the armed conflict and result in avoidable loss of life. Hence, argues Ha'amek She'elah, any person defying Joshua would, in effect, have been an aggressor (rodef) whose disobedience would have endangered the entire nation. Sanctions imposed upon the miscreant were designed to restore Joshua's courage and confidence by eliminating any challenge to his authority.

That is that He commanded us to appoint a king upon us - [that] he gather all of our nation and lead us. And that is His, may He be blessed, saying, "You surely may set a king over you" (Deuteronomy 17:15). And the language of the Sifrei already preceded us (Sifrei Devarim 67:1), "Three commandments were commanded to Israel upon their entrance to the land: To appoint a king over them; to build the [Temple]; and to cut off the seed of Amalek." And the [further] language of the Sifrei (Sifrei Devarim 157:6) is, "'You surely may set a king over you' [...] - that his awe be over you." And [likewise] that we place in our hearts about him, the utmost honor, glory, praise and status of the highest magnitude which has nothing above it - until his level for us is greater than the level of one of the prophets that will be in his generation. Anytime that the commandment of the king does not contradict a commandment of the Torah, we are surely obligated to listen to his commandment. And one who transgresses his commandment and does not listen to him is surely fit - and it is permissible - for the king to kill [him] as he wishes; and as Israel said about themselves (Joshua 1:18), "Any man who flouts your commands, etc." And anyone who rebels against the monarchy can have his blood avenged by a king who was established according to the Torah. And the regulations of this commandment have already been explained in Sanhedrin and in Chapter 1 of Keritot and 7 of Sotah. (See Parashat Shoftim; Mishneh Torah, Kings and Wars 1.)