Thematic Bible: What is not vain

And when Moses had spoken all these words unto the end to all Israel, then he said unto them, "Set your hearts unto all the words which I testify unto you this day: that ye command them unto your children, to observe and do all the words of this law. For it is not a vain word unto you: but it is your life: and through this word ye shall prolong your days in the land whither ye go over Jordan to conquer it."