These passages parallel each other and form a two-part introduction to the main section (Judges 3:7 – 16:31). It reveals how the Israelites fared in their attempt to complete the conquest of Canaan by taking the areas that had been allotted to them by Joshua (Joshua 13:1 – 19:51), from which this section draws parts of its material.1
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?”