The books of Joshua and Judges provide religious perspective on Israel's successes and failures from the time that Joshua begins to lead the Israelites after Moses's death until the rise of the monarchy. The stories of these two books show the God of Israel still guiding the life of his people.
In Genesis, God makes a twofold promise to Abraham: many descendants and the making of a great nation (Gen 12:2ff). In the book of Joshua, we find this promise brought to this fulfillment as the Israelites come to Canaan, the land of promise.
During the span of the 150 years covered in Judges, considerable importance is attached to the religious and political development of the tribal life of the Israelites. This is well before the time of national unity; in Judges, the people are bound together solely by their faith in YHWH.
In this rich and insight-filled commentary, Roland Faley draws out the Deuteronomistic thesis in Joshua and Judges: A people of faith, even if they wander, cannot fall.