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. For Joshua 23, the faithfulness of God is highlighted with the mention of past victories as well as the promise of future help. In light of this, God’s people are encouraged to separate themselves from the pagan nations. For us today, we can understand this as a call to fight against our sinful desires and to realize that pagan religions lead away from God and that which is true. We must make an active effort to obey the Lord, to live in the places where he has put us, but not to become like the unbelievers around us.
1 A long time afterward, when the LORD had given rest to Israel from all their surrounding enemies, and Joshua was old and well advanced in years,