Judges 1-3: You've Got To Serve Somebody

By God's design, the Israelites did not conquer all of the inhabitants of the land. They were left to test the Israelites to see whether they would obey the LORD's commands, which he had given their forefathers through Moses.  - Judges 3:4 NIV

As long as Joshua and the generation that had seen God bring them into the promised land were alive, the Israelites followed after God. But once, that generation was gone, they looked around and saw the inhabitants that had not been driven out.  They saw their gods.  They saw their affluence.  They saw their beautiful daughters.  First their eyes, then their hearts followed after what remained in the land.  They took their daughters in marriage and gave their own daughters to their sons, and served their gods. - Joshua 3:6 NIV

The result was temporary prosperity then defeat at the hands of their enemies.  After they cried for help, a godly judge would come along and their hearts would turn to the Lord.  They would experience peace and prosperity while that judge was alive.  Once the judge was dead, they would follow whoever and whatever captured their fancy until their hearts and fortunes became bankrupt once more. 

It may be the devil,

It may be the Lord,

But you gotta serve somebody - Bob Dylan