As Joshua assumes leadership, God empowers him for the historic mission of conquering and dividing the land. A transition occurs from an ancient divine promise to a practical reality, with Joshua assured that he is destined to complete this monumental task. The divine call for strength and bravery is a directive to gather inner power [מצודת ציון]. This involves a two-step process: an initial awakening of might, followed by the endurance to maintain that courage over time [מלבי״ם].
The primary approach among commentators is that this directive is not about military bravery on the battlefield. Instead, it refers to the strength required to lead the people in social and civil matters [רש״י, מצודת דוד]. The central challenge of dividing the land naturally sparks arguments, legal disputes, and friction among the people. Consequently, Joshua requires immense inner fortitude to stand firm and lead justly, without fearing or backing down from anyone during the distribution process [אברבנאל, מלבי״ם].
God also instills confidence in Joshua regarding the mission's ultimate success. Unlike typical historical conquests that can span multiple generations, Joshua receives a guarantee that he will personally oversee the completion of this primary task [ביאור שטיינזלץ]. This assurance rests on three solid foundations that eliminate any reason for fear: a chosen leader to distribute the inheritance, a chosen people to receive it, and the land itself, which carries a divine oath that will not remain unfulfilled [מלבי״ם].
From a different perspective, the physical war to conquer the land is considered easier than the internal human struggle against negative inclinations. God explains to Joshua that he simply needs to remove fear from his heart, and true bravery will be provided by God. Ultimately, Joshua serves only as the mediator and distributor. It is God Himself who fights the battles and delivers the land, fulfilling His ancient oath to the forefathers [אלשיך].
This mission defines Joshua's unique historical status. Even though he did not achieve the same level of prophecy as his teacher Moses, his ultimate greatness and perfection are realized through the immense privilege of granting the land to the Israelites and bringing God's ancient promise to life [אברבנאל].