What is the master [within you] who at this very moment is seeing and hearing? If you reply, as most do, that it is Mind or Nature or Buddha or one's Face before birth or one's Original Home or Koan or Being or Nothingness or Emptiness or Form-and-Color or the Known or the Unknown or Truth or Delusion, or say something or remain silent, or regard it as Enlightenment or Ignorance, you fall into error at once. What is more, if you are so foolhardy as to doubt the reality of this master, you bind yourself though you use no rope. However much you try to know it through logical reasoning or to name or call it, you are doomed to failure. And even though all of you becomes one mass of questioning as you turn inward and intently search the very core of your being, you will find nothing that can be termed Mind or Essence. Yet should someone call your name, something from within will hear and respond. Find out this instant who it is!
If you push forward with your last ounce of strength at the very point where the path of your thinking has been blocked, and then, completely stymied, leap with hands high in the air into the tremendous abyss of fire confronting you -- into the ever-burning flame of your own primordial nature -- all ego-consciousness, all delusive feelings and thoughts and perceptions will perish with your ego-root and the true source of your Self-nature will appear. You will feel resurrected, all sickness having completely vanished, and will experience genuine peace and joy.

- Bassui, Zen Master (1327-1387)