DEUT268 … review of the Talmud [is] in fulfillment of [this verse]: "'And you shall teach them [v'shinantam] to your children' -- words of Torah should be sharp [sh'nunim] in your mouth, so that if someone asks you something you should not answer hesitatingly, but outright" (Sifri Devarim ibid., Kiddushin 30a). It is impossible that mitzvos be "sharp" and ready in one's mouth for a response to questioners without many repetitions, as our Sages stated (Chagigah 9b): "One who reviews his lesson 100 times cannot be likened to him who has reviewed it 101 times."