Shobogenzo Shoaku-Makusa 13: Children Babbling Dharma.
Kyo-i asks, “What is the Great Intention of the Buddha-Dharma?” Dorin says, “Not to commit wrongs. To practice the many kinds of right.” Kyo-i says, “If it is so, even a child of three can express it!” Dorin says, “A child of three can speak the truth, but an old man of eighty cannot practice it.” Thus informed, Kyo-i makes at once a prostration of thanks, and then leaves . Master Dogen concludes his discussion of this koan and his talk on 'not doing wrongs, doing right'... A master of the past says, “Just at the time of your birth you had your share of the lion’s roar.” “A share of the lion’s roar” means the virtue of the Tathagata to turn the Dharma-wheel, or the turning of the Dharma-wheel itself. Another master of the past says, “Living-and dying, coming-and-going, are the real human body.” So to clarify the real body and to have the virtue of the lion’s roar may truly be the one great matter, which can never be easy. We are born and die with a body with which to clarify th...