Delusion, enlightenment, training, life, death, Buddhas and all living things are in existence when there is Buddhism; none of the above exist when all is within the Truth; since the Way of the Buddha transcends unity and duality, all of the above exist; whilst we adore flowers they wither; weeds grow strong whilst we long for their destruction. When we wish to teach and enlighten all things by ourselves, we are deluded; when all things teach and enlighten us, we are enlightened: to enlighten delusion is to become Buddha; most living things are deluded within enlightenment — some are enlightened within enlightenment; others deluded within delusion. There is no need to know that one is identical with Buddha when Buddha is truly Buddha for a truly enlightened Buddha expresses his Buddhahood in his daily life: to observe objects and voices, with complete awareness of body and mind, is very different from seeing a reflection in a mirror or the moon reflected in water; even if you see one side of something the other will still be in shadow.
When one studies Buddhism, one studies oneself; when one studies oneself, one forgets oneself; when one forgets oneself, one is enlightened by everything and this very enlightenment breaks the bonds of clinging to both body and mind not only for oneself but for all beings as well.
(Excerpt from Genjo-koan, The Teachings of Dogen Zenji in Zen is Eternal Life by Roshi P. T. N. H. Jiyu-Kennett, published by Shasta Abbey Press, 1999)