Moses said to him in the face of all Israel Lest any should question or deny his authority after Moses's death. Be strong and of good courage The same exhortation and promise are given to him in particular, that were before given to them all, because he was to bear the charge of them all, and the toil and burden of governing them, and conducting their affairs.
Related Commentaries of Deuteronomy 31:7
Deuteronomy 31:7
7 And Moses called unto Joshua, and said unto him in the sight of all Israel, Be strong and of a good courage: for thou must go with this people unto the land which the LORD hath sworn unto their fathers to give them; and thou shalt cause them to inherit it.