The book opens by basically saying, Here’s what happened after the death of Joshua.
More often, new beginnings are marked by the death of God’s servants: Exodus begins with Joseph’s death, Joshua with Moses’ death, Judges with Joshua’s death, and 1 Kings with David’s death. Yet in spite of all that, God's kingdom does not fall to pieces, not even when Sheol takes God’s most useful servants. The kingdom of God continues though the servants of God die.
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1 After the death of Joshua, the people of Israel inquired of the LORD, “Who shall go up first for us against the Canaanites, to fight against them?”