For it is not a vain thing for you; because it is your life: and through this thing ye shall prolong your days in the land, whither ye go over Jordan to possess it. Through this thing ye shall prolong your days - Instead of being cut off, as God here threatens, ye shall be preserved and rendered prosperous in the land which, when they passed over Jordan, they should possess.
Related Commentaries of Deuteronomy 32:47
Deuteronomy 32:47
47 For it is not a vain thing for you; because it is your life: and through this thing ye shall prolong your days in the land, whither ye go over Jordan to possess it.