King James Version
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.English Standard Version
For it is no empty word for you, but your very life, and by this word you shall live long in the land that you are going over the Jordan to possess."New International Version
They are not just idle words for you-they are your life. By them you will live long in the land you are crossing the Jordan to possess."