Know this: Buddha is this mind. Outside of this mind there is no Buddha. Briefly, I suggest that there are five basic principles.
First: Know the essence of mind. The essential nature is pure. The essence is itself Buddha.
Second: Know the function of mind. Its function gives rise to the jewel of Dharma. It functions without obstruction, but is always still; even the ten thousand delusions are in essence just this.
Third: Constant Awakening is without end. The Awakening mind is always present. The Teaching of this Awakening is without form.
Fourth: Always know the body is empty and tranquil. Inside and outside are transparent to each other. Your body arises in the midst of ultimate reality. There have never been obstacles.
Fifth: Keep unified-mindfulness without deviation. Both movement and stillness go nowhere.
Those who practice this will clearly see their Buddha-nature and enter into the gate of practice without hesitation.
---by the Fourth AncestorZen Patriarch Dayi Daoxin (580-651)