When one displays the buddha mudra with one's whole body and mind, sitting upright in this samadhi even for a short time, everything in the entire dharma world becomes buddha mudra, and all space in the universe completely becomes enlightenment. Therefore, it enables buddha-tathagatas to increase the dharma joy of their own original grounds and renew the adornment of the way of awakening. Simultaneously, all living beings of the dharma world in the ten directions and six realms become clear and pure in body and mind, realize great emancipation, and their own original face appears. At that time, all things together awaken to supreme enlightenment and utilize the buddha-body, immediately go beyond the culmination of awakening, and sit upright under the kingly bodhi tree. At the same time, they turn the incomparable, great dharma wheel and begin expressing ultimate and unfabricated profound prajna.
From: Talk on the Wholehearted Practice of the Way -
Kosho Uchiyama (with Shohaku Okumura, Taigen Daniel Leighton)
[The practice] thus increases the Dharma-joy that is the original state of the buddha-tathagatas, and renews the splendor of their realization of the truth. From: Bendowa - A Talk about Pursuing the Truth - Nishijima-Cross