The book of Joshua is a very positive book in the Bible. It’s a book about the faithfulness of God, written to strengthen our faith in his promises, particularly the promise that Jesus Christ is preparing a new home for us where we can enjoy rest in his presence (Hebrews 4:1–16). It is also a book about our responsibility towards God. The Lord has made promises to us, he has shown himself to be worthy of our trust, and in this book we will see how the Lord calls us to now be faithful to him.
In light of the purpose of Joshua, the goal of your sermon must be to show how God has been faithful to us, and what response the Lord is calling us to. Joshua 11:16–23 focuses our attention on God’s sovereign power and might. He can be trusted because he is supremely powerful, he is sovereign even over his enemies. God’s sovereignty should encourage us to obedience, even if it might mean trouble because we know that nothing can separate us from his love (Romans 8:31–39).
16 So Joshua took all that land, the hill country and all the Negeb and all the land of Goshen and the lowland and the Arabah and the hill country of Israel and its lowland