The children of Joseph said, The hill-country is not enough for us: and all the Canaanites who dwell in the land of the valley have chariots of iron, both they who are in Beth-shean and its towns, and they who are in the valley of Jezreel.
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.