A quick reading of Joshua 1:1 – 12:24 gives the impression that the fighting in Canaan was completed very quickly, as if the battles were finished in a matter of weeks or months. However, Joshua 11:18 as well as Joshua 22:3 make it clear that the conquest took a long time. Most likely, the campaign took at least five years. In Joshua 14:1–15, Caleb, one of the original spies sent into the land (Numbers 13:30–31), is about to receive his inheritance. He claims (Joshua 14:10) that it has been forty-five years since he spied out the land. If the wilderness wandering was forty years (Numbers 14:34) then the entire campaign lasted at least five years. A long invasion is consistent with the promise of God in Exodus 23:29–30. The Lord would drive out the inhabitants of Canaan bit by bit so that the land itself would not become desolate and full of wild beasts.
3 You have not forsaken your brothers these many days, down to this day, but have been careful to keep the charge of the LORD your God.