The book of Joshua is a very positive book in the Bible. It is 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 toward 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 15:1–63 focuses on realizing that God has placed us exactly where we are today and that he wants us to serve him in our present circumstances.
1 The allotment for the tribe of the people of Judah according to their clans reached southward to the boundary of Edom, to the wilderness of Zin at the farthest south.