Deuteronomy 6:1-3: “Now this is the commandment, and these are the statutes and judgments which the Lord your God has commanded to teach you, that you may observe them in the land which you are crossing over to possess, 2 that you may fear the Lord your God, to keep all His statutes and His commandments which I command you, you and your son and your grandson, all the days of your life, and that your days may be prolonged. 3 Therefore hear, O Israel, and be careful to observe it, that it may be well with you, and that you may multiply greatly as the Lord God of your fathers has promised you—‘a land flowing with milk and honey.’
Because God is God, the absolute lord and law-giver, fear of God is the essence of sanity and common sense. To depart from a fear of God is to lack any real sense of reality. -RJ Rusdoony "Institutes of Biblical Law"
One might call it a miracle, but actually its just Living wisely. Living wisely prolongs lifespan. It means knowing how to live, the purpose and meaning of our life. Your life depends on wisdom for strength and vitality. Wisdom "is a tree of life to those who take hold of her, And happy are all who hold her fast."
The reason for the giving of these commandments is to awaken the fear of God, and that fear might prompt obedience. Because God is God, the absolute lord and law-giver, fear of God is the essence of sanity and common sense. To depart from a fear of God is to lack any sense of reality. Second, "The maintenance of the fear of God would bring prosperity, and increase of the nation promised to the fathers.....The increase of the nation had been promised to the patriarchs from the very first." It is therefore necessary to maintain this fear and obedience from generation to generation.