We see various examples of Judges being anointed by God to lead Israel against the oppressive kings of other nations, despite their disobedience to God. We learn a few lessons here:
1. The people of Israel drifted away from God after the death of their leaders, Moses & Joshua. We need the counsel of godly leaders and spiritual leadership to lead us accurately with God.
2. The 2nd generation of Israelites did not know the greatness of the God of their fathers; one needs to have a personal relationship with God, especially in families.
3. The Israelites took Canaanite women as wives and were eventually seduced into idolatry. One should not be unyoked with a non-believer, but marry a person who shares the same faith and love as you have for God.
4. The Israelites were seduced by what they saw, the Canaanites and their idols and they started taking part in their sinful practices. We should learn to be careful not to put your faith on things which are visible (eg. job, money, idols). These in turn can lead us away from God.