311 Moses went on and addressed these words to all Israel. 2 He said, "I'm 120 years old today. I can't get about as I used to. And God told me, 'You're not going to cross this Jordan River.' 3 "God, your God, will cross the river ahead of you and destroy the nations in your path so that you may dispossess them. (And Joshua will cross the river before you, as God said he would.) 4 God will give the nations the same treatment he gave the kings of the Amorites, Sihon and Og, and their land; he'll destroy them. 5 God will hand the nations over to you, and you'll treat them exactly as I have commanded you. 6 "Be strong. Take courage. Don't be intimidated. Don't give them a second thought because God, your God, is striding ahead of you. He's right there with you. He won't let you down; he won't leave you."
Matthew Henry's Commentary on Deuteronomy 31:1-6
Commentary on Deuteronomy 31:1-8
(Read Deuteronomy 31:1-8)
Moses assures Israel of the constant presence of God with them. This is applied by the apostle to all God's spiritual Israel, to encourage their faith and hope; unto us is this gospel preached, as well as unto them; he will never fail thee, nor forsake thee, Hebrews 13:5. Moses commends Joshua to them for a leader; one whose wisdom, and courage, and affection they had long known; one whom God had appointed to be their leader; and therefore would own and bless. Joshua is well pleased to be admonished by Moses to be strong and of good courage. Those shall speed well, who have God with them; therefore they ought to be of good courage. Through God let us do valiantly, for through him we shall do victoriously; if we resist the devil, he will flee from us.