The Book of Deuteronomy was Moses’ last great public act in Israel. When it concluded, he would passed the leadership of the people to Joshua and they will go from his tutelage in the wildness to possess the promised land. At this time of great transition, one of the repeated encouragements for both Joshua and the people is to “be strong and courageous.”
Deut 11:8“You shall therefore keep every commandment which I am commanding you today, so that you may be strong and go in and possess the land into which you are about to cross to possess it”
“Be strong and courageous” will occur again in Deuteronomy in 31:6 & 7 and 31:23. Then again inJoshua 1:6,7,9 & 18, and 10:25.
As the people go from facing every challenge together as a whole group with a leader who had face to face communication with God, to 12 tribes each comfortably distant from each other to allow for a great national growth and the leadership of a faithful man, but not one who is the great deliverer and law giver, they will need to be assured and act confidently. They will need more courage than wandering in the wilderness ever demanded. Since they would need a confident faith, Moses and God Himself supplied them with as much encouragement as possible.