In Genesis 12 God calls Abram (Abraham) and promises to make him into a great nation by whom all peoples will be blessed. He also promises to give his descendants the land of Canaan (12:6-7). In Gen 15:16 is the suggestion that the current inhabitants of the land are living on borrowed time for their rebellion against God.
Several hundred years later, Abraham's descendants have become a great nation and are ready to take possession of the land God promised. The sin of the inhabitants has reached its 'full measure', and God has already judged and expelled them for it, see Lev 18:24-28 (cf Deut 18:9-12).
Israel's "taking possession" of the land God was "giving" them would require them going to war against the inhabitants. This is the original "holy war". Unlike all subsequent 'holy wars' Israel's battle for the "Promised Land" was indeed an holy war because she was, uniquely, both a physical and a spiritual State, an earthly kingdom and God's Kingdom. Israel was the first and only true Theocracy, her war was holy war. And as shown, it was not merely a territorial 'land-grab', it was the exacting of God's judgement on the sins of the inhabitants, as well as the fulfilling of his purposes for his people.
The book of Joshua chronicles the initial conquest of the Land, and it's allotment to the 12 tribes of Israel (see map). Judges is what happens next.
The conquest of the Land was always intended by God to take a period of time (Ex 23:29-30). But as Judges proceeds, we quickly realise that the ideal set out in Joshua, ie of all Israel established in their allotted inheritance, would remain just that, an ideal.
Israel was constantly warned to completely removed the inhabitants of the land or they and their religious practices would be a "snare" to them, see Ex 23:20-33, 34:11-16, and particularly see Josh 23. The story of the Judges is what happens when Israel failed to heed these warnings.
1:1-2:5 Introduction and setting; Israel's failure to keep God's covenant when entering the land, God's summation of its significance.
2:6-16:31 The Judges
God's punishment through oppression by the remaining inhabitants and
neighbouring nations, and his deliverance through 12 Judges;
17-21 Two Tribal Movements
1 What picture of God does the book paint? ie what characteristics are emphasised?
2 How does the book ready us for Jesus?
3 Judges comes before the monarchy is established in Israel (1&2 Samuel). How does the book view kingship? Favourably? Unfavourably? What examples are given?
4 What kind of people are the Judges? Would you expect to be the "heroes" of God's people? What does this teach us about God's salvation (cf 2 Cor 4:7; Isa 52:2-3)
5 How are God's people governed in this period? What do you think of this? Why does God do things this way?