Israel's obedience was to be more than skin deep. It was to be a matter of the mind and will. Israel was not to forget their experience of God; they were to be diligent to preserve their memory of him. In addition, they had a duty to teach their children and grandchildren about it.
9 “Only take care, and keep your soul diligently, lest you forget the things that your eyes have seen, and lest they depart from your heart all the days of your life. Make them known to your children and your children’s children