Investing Authority in the Next Guy (or Gal)
18 So the Lord said to Moses, “Take Joshua the son of Nun, a man in whom is the Spirit, and lay your hand on him. 19 Make him stand before Eleazar the priest and all the congregation, and you shall commission him in their sight. 20 You shall invest him with some of your authority, that all the congregation of the people of Israel may obey. 21 And he shall stand before Eleazar the priest, who shall inquire for him by the judgment of the Urim before the Lord. At his word they shall go out, and at his word they shall come in, both he and all the people of Israel with him, the whole congregation.”
When leadership of Israel passed from Moses to Joshua, God told Moses to pray and lay hands on Joshua. In front of all of the people, Moses would “invest him with some of [his] authority.”
The fact is, Moses had been investing Joshua with authority for years. What was done in front of all of the people was just the ceremony to show that the work was done.