Chariots of iron were not made entirely of iron but wood with iron reinforcement.1 They would be particularly effective on level ground but not in the hills. These chariots are mentioned as a reason for why the people of Joseph could not drive out the Canaanites. This reason has, however, already been shown to be false (see Joshua 11:9). With the Lord helping them, they could have driven the Canaanites from the land. They had the power to remove them and serve as God’s instruments of war but preferred the peace that comes from tolerating wickedness to war for righteousness.2
16 Les fils de Joseph dirent: La montagne ne nous suffira pas, et il y a des chars de fer chez tous les Cananéens qui habitent la vallée, chez ceux qui sont à Beth-Schean et dans les villes de son ressort, et chez ceux qui sont dans la vallée de Jizreel.