4.19 Judges -- Limits of Conquest
Judah continued to be aggressive after Joshua's death. This tribe conquered the city of Jerusalem (Judg 1:8), and also Gaza and other cities. Yet the first chapter of Judges lists all the Canaanites who were not driven out. Some of them were forced into slavery (Judg 1:28-30, Judg 1:35), but they were not destroyed or expelled.
The Kenites, descendants of Jethro, Moses' father-in-law, moved into the Negev and "settled with the people" (Judg 1:16). The Kenites were an example of the alien or sojourner -- not Israelites, but allied peoples who resided with Israel in harmony with her law. They figured prominently in the judgeship of Deborah (4.2.8).
The failure to displace the Canaanites does not seem to be due to a lack of ability, but of initiative. God sent his angel to scold the people at a place called Bokim (Weepers) (Judg 2:1-5). Surely this angel did not appear to the entire assembly. So we wonder -- who did this angel speak to? Possibly Joshua was still alive at this time, since Judg 2:6-9 repeats the account of his death. The angel declared that Israel had disobeyed the Lord by cohabiting with the nations, and that no longer would He help drive out the inhabitants of the land, but they would be a snare to Israel. The people responded by weeping and offering sacrifice. But it was too late -- as their parents had disobeyed God by turning back from entering Canaan, so the door of opportunity to conquer the land had closed for this generation. The people's apathy had derailed the divine timetable.