Israel would need a new leader to be appointed in Moses' place, to lead them into the Promised Land. Joshua, the servant/assistant of Moses, would be the one to take his place. God called Moses to encouraged Joshua for the task that was ahead of him, a task (causing Israel to inherit the land) that Moses often said how much he wished he could perform.
38 Joshua the son of Nun, who stands before you, he shall enter. Encourage him, for he shall cause Israel to inherit it.