Not vain — It is not an unprofitable or contemptible work I advise you to, but well worthy of your most serious care.
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.