The inability of Moses to go over Jordan, and the ability of Joshua, should be well noticed by the Reader. As Moses' natural strength was not diminished, certain it is, his want of strength was not the cause; neither was the personal power of Joshua the reason of these things. But if we look at Moses as typical of the law, and Joshua as typical of JESUS and his gospel: then we see how impossible it was for the law to bring souls to GOD, and how suited alone that Almighty Joshua is, to plant his people in his holy mountain. For the law made nothing perfect; but a better hope did, by which we draw nigh unto GOD. Hebrews 7:19.
Related Commentaries of Deuteronomy 31:7
Deuteronomy 31:7-8
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.
8 And the LORD, he it is that doth go before thee; he will be with thee, he will not fail thee, neither forsake thee: fear not, neither be dismayed.