The purpose of exalting Joshua is so that Israel would know that the Lord was with him in a special way.1 It was thus meant to encourage the obedience of the Israelites to the words of Joshua since Joshua himself was being told what to do by the Lord. Obedience to Joshua would thus be obedience to the Lord.
7 The LORD said to Joshua, “Today I will begin to exalt you in the sight of all Israel, that they may know that, as I was with Moses, so I will be with you.