Shobogenzo Shoaku-Makusa 11: Right is Not a Theory in the Head.

Master Dogen is concluding his discussion of 'not doing wrong, doing right' by looking at this koan...

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.

His commentary begins:

Kyo-i, though descended from Haku Shogun, is truly a wizard of the verse who is rare through the ages. People call him one of the twenty-four [great] men of letters. He bears the name of Manjushri or bears the name of Maitreya. Nowhere do his poetical sentiments go unheard and no-one could fail to pay homage to his authority in the literary world. 

Master Dogen praises Kyo-i for his great reputation and his talent in writing, but he's going to open a can of whip-ass on him for his conduct in this koan... and here it comes:

Nevertheless, in Buddhism he is a beginner and a late learner. Moreover, it seems that he has never seen the point of this “Not to commit wrongs. To practice the many kinds of right,” even in a dream. Kyo-i thinks that Dorin is only telling him “Do not commit wrongs! Practice the many kinds of right!” through recognition of the conscious aim. Thus, he neither knows nor hears the truth that the time-honored [teaching] of the not committing of wrongs, the good doing of rights, has been in Buddhism from the eternal past to the eternal present. He has not set foot in the area of the Buddha-Dharma. He does not have the power of the Buddha-Dharma. Therefore he speaks like this.

Master Dogen uses poor Kyo-i as a bit of a whipping boy here against a shallow, intellectual understanding of what Master Dorin is indicating... Dorin is talking about 'not committing wrongs, practicing right' on the basis of a lifetime of zazen practice, and the very practical fact that, after all that, we're still imperfect humans and sometimes fall down in this ('a man of eighty can't practice it!')

Thinking and spouting grand theories and pithy religious axioms is not the same as our actual doing. 

Even though we caution against the intentional commitment of wrongs, and even though we encourage the deliberate practice of rights, this should be in the reality of 'not committing'.

We observe the Precepts and 'not doing wrong, doing right' in Zen practice, but to be consistent with the foundational view of Buddhism this is based in the practice of 'dropping off body and mind' in zazen where we can learn directly that we needn't act on our thoughts and feelings and urges, the stuff we might usually identify with as our personalities or our self.