The Deuteronomy book ends with the death of Moses and the nation of Israel looking up to Joshua his faithful aide as their new leader, and then the book of Joshua starts with God’s marching orders for him and his people.
In verses one through five the Lord told Joshua to go and take possession of the land; in verses six through eight God encouraged Joshua repeating twice to “be strong and courageous” and reminding him of God’s promise to his forefathers; In verse nine I think our Lord can see how scared Joshua was because He is already questioning him “Have I not Commanded you?” then he tells him for the third time “Be strong and courageous” adding “Do not be terrified, Do not be discouraged” ending His encouragement with the most comforting promise anybody can get “The Lord your God will be with you wherever you go”.