Judges has the well-known repeated cycle of
1. sin of the people
2. people given over to their sin
3. resultant oppression
4. their crying out
5. deliverance through a Saviour.
Going through the book, I've been very struck not just by the weakness of the people, but the dependence of the people. What I mean is that, at first, I got thinking about how the people are pretty rubbish at following God (and surely I mustn't be like that!). But, actually, it dawned on me: isn't that what the gospel says i.e. that I'm pretty rubbishing at obeying God? Rather than merely girding my loins to be better, I need to see my dependence upon a Saviour.
All through Judges you see that the Saviour restrains sin and evil, but when he/she goes it all breaks down. The danger here is that I try to better than Israel without a "Judge" to lead me. All this teaches me that I need Jesus - my great Saviour - and without Him everything will break down! He's the One who breaks the cycle and He never goes away. He is the eternal Saviour who brings "rest to the land" forever. I need to be better - but I cannot be better without Him. I am dependent upon the Great Judge.