but the hill-country shall be yours; for though it is a forest, you shall cut it down, and the goings out of it shall be yours; for you shall drive out the Canaanites, though they have chariots of iron, and though they are strong.
The writer of the Book of Joshua noted carefully the failures of the tribes to drive the Canaanites out of their territories, as well as their successes in doing so (e.g., Caleb). The extent of their occupation of their land depended on the extent of their ability to annihilate the Canaanites by God’s power.