The transition of leadership from Moses to the Israelites as they prepare to enter Canaan brings a promise of victory, but it also comes with a clear demand for action. God promises to deliver the inhabitants of the land to the Israelites [ביאור שטיינזלץ]. However, this divine help requires the people to strike the nations with their own hands [העמק דבר, מלבי״ם]. This shift to independent action is directly tied to the fact that Moses will not cross the Jordan River. Had Moses entered the land with them, the enemy nations might have been wiped out through miracles alone, simply by his spoken word. With his approaching death, the practical responsibility now rests upon the nation [העמק דבר]. Ultimately, God hands the enemy over to the Israelites specifically so they can actively carry out His instructions [מלבי״ם].
The requirements placed upon the people involve a complex set of laws. The primary approach among commentators is that the main instruction is the physical destruction of the land's inhabitants, leaving no one alive. Alongside this, they are required to completely remove all traces of idolatry. This includes breaking monuments, smashing altars, cutting down sacred trees, and erasing the very names of these practices from the land. Furthermore, there is a strict ban on making treaties or intermarrying with the local nations [אבן עזרא, בכור שור, ביאור יש״ר].
Despite these strict instructions, total destruction is not the immediate first step. According to the laws of war, the Israelites must first offer peace to these nations. Only if the inhabitants refuse the offer and choose to fight are they to be wiped out. If the local populations reject peace but prefer to flee rather than fight, there is no obligation to kill them. In fact, during a siege, an escape route must be left open so they have the opportunity to run away [רלב״ג, ביאור יש״ר].
The conquest of the land is not expected to be a fast process. The nations will not be destroyed immediately, preventing wild animals from multiplying in the empty spaces. Additionally, the complete capture of the land could be delayed by the future mistakes of the Israelites. Because of this extended struggle, the people need exceptional bravery. They must gather their courage and refuse to fear the nations or the spiritual forces that represent them. God promises that He will not abandon them to these spiritual entities. Their safety and success in battle rest on two main strengths: the power of their large numbers, and their complete unity in accepting the kingship of God [שפתי כהן].