Joshua 11 reports the northern campaign. Jabin king of Hazor summons a vast coalition to the waters of Merom, as many as the sand that is on the seashore, with very many horses and chariots. Against so great an army, Yahweh says, Don't be afraid because of them; for tomorrow at this time, I will deliver them up all slain before Israel. God also commands that their chariots be burned with fire.
Hazor, the head of all those kingdoms, falls as God's judgment. The chapter is honest that the war took a long time; only Gibeon made peace. Verse 20 explains that it was of Yahweh to harden the kings' hearts to come against Israel in battle, that they might have no favor, as Yahweh commanded Moses. The Anakim, whose size had terrified the spies decades earlier, are cut off from the hill country.
The center of the chapter is obedience passed down faithfully: As Yahweh commanded Moses his servant, so Moses commanded Joshua. Joshua did so. He left nothing undone of all that Yahweh commanded Moses. The chapter closes with a summary: So Joshua took the whole land, according to all that Yahweh spoke to Moses; and Joshua gave it for an inheritance to Israel. Then the land had rest from war. In the New Testament, Joshua's rest points to a greater rest: There remains therefore a Sabbath rest for the people of God (Hebrews 4:9).