After that whole generation had been gathered to their fathers, another generation grew up, who knew neither the Lord nor what he had done for Israel. Then the Israelites did evil in the eyes of the Lord and served the Baals (Judges 2:10,11 NIV).
A lot of important things are to be learned here. The first lesson is that there is a great responsibility on the elder generation. They are to teach their next generation about God and about His wonderful and mighty works on behalf of those who trust him. The younger generation should be taught this. So, a great responsibility rests on the shoulders of priests, teachers and parents.
When a generation grows up without knowing the Lord and His goodness, the tendency is quite naturally to do evil. Sinful ways and false worship will abound. When this happens enemy forces of evil will always conquer the minds and hearts of people. They will be unable to resist the schemes of the devil. And instead of victory, such a generation will always taste defeat.
Again, there is yet another solemn thought hidden in these lines. It is this that, we at our best can only influence our own generation. Joshua and the elders of that generation kept the eyes of the people focussed on God and His works on their behalf. But when they were dead and gone, the people went to evil ways. So the thought here is that, if we waste our time and opportunities to serve God and help others to love God, we may never get another chance to do so. And both generations will perish. So it is the solemn responsibility of a generation that knows God and His miracles on their behalf to pass on the torch of faith; alive and aflame, into the hands of the next!