The book of Joshua begins with God choosing the next leader for His people.
After the death of Moses the servant of the LORD, the LORD said to Joshua the son of Nun, Moses’ assistant, “Moses My servant is dead. Now therefore arise, go over this Jordan, you and all this people, into the land that I am giving to them, to the people of Israel” (Joshua 1:1-2).
Israel remembers the lessons of forty years of wilderness wanderings. Therefore, broadly speaking, the people under Joshua respect and obey the Lord.
Israel served the LORD all the days of Joshua, and all the days of the elders who outlived Joshua and had known all the work that the LORD did for Israel (Joshua 24:31 cf. Joshua 11:15).
As we survey roles, it becomes obvious that the law of Moses sets the stage.
Only be strong and very courageous, being careful to do according to all the law that Moses My servant commanded you. Do not turn from it to the right hand or to the left, that you may have good success wherever you go. This Book of the Law shall not depart from your mouth, but you shall meditate on it day and night, so that you may be careful to do according to all that is written in it (Joshua 1:7-8).