DEUT272 Learn and teach Torah. Learn the wisdom of the Torah and teach it to your children. Learn how to fulfill the mitzvos properly and not transgress the Torah’s prohibitions, achieving true understanding of the Torah's laws. How is this accomplished? Expounding this verse, our Sages answer, “By learning and reviewing the Torah to the degree that it is all on the tip of your tongue, such that if anyone asks you a question about it, you are able to answer him without stuttering, without any hesitation.” This is how one teaches the Torah towards children and pupils-- reviewing it with them until they, too, can answer any question, without hesitation. Key concept: Through Torah learning one comes to understand the ways of Hashem. Without Torah learning, one can never obtain such knowledge. One is left void of understanding, like an animal. He who violate this mitzvah and does not teach his son Torah nullifies a positive precept of the Torah. So, too, anyone who has the opportunity to learn [or teach] and fails to do so. Such a person's punishment is very great, for Torah learning is the mother of all of the other mitzvos.