31:3
“The Lord your God will cross over ahead of you.” All of Israel’s history and life needs to be understood within the context of what God is doing, as do our own lives. We can perhaps see a parallel of this in death. Jesus had died and rose again, He has conquered death. Jesus went ahead of us. God would destroy the nations, and they would take possession of the land. So, as always, we see God doing something and then the people doing something. God is the author and pioneer of His plans for us, but we are actively involved in them. “Joshua also will cross over ahead of you”. Joshua is the leader, and a representative of the Lord.
31:4,5
The Lord had already demonstrated His willingness and ability to do these things in the defeat of the Amorite kings, Sihon and Og. Lesser incidents in our lives are sometimes preparing us for greater events. The lands would be delivered into Israel’s hands, but they must also obey all the commands.