At the behest of the King, T'aego gave a brief outline of the basic principles of Zen:
There is something bright and clear, without falsity, without biases, tranquil and unmoving, possessed of vast consciousness, fundamentally without birth and death and discrimination, without names and forms and words. It engulfs space and covers all of heaven and earth, all of form and sound, and is equipped to function.
If we speak of its essence, it is so vast it embraces everything, so that nothing is outside of it. If we speak about its function... even great sages cannot get to the end of it.
This one thing is always with each and every person. Whether you move or not, whenever you encounter circumstances and objects, it is always very obvious and clear, clear everywhere, revealed in everything. It is quietly shining in all activities. As an expedient, it is called Mind. It is also called the Path, and the king of the myriad dharmas, and Buddha. Buddha said that whether walking, sitting or lying down, we are always within it.
Even Yao and Shun said: "Holding faithfully to the mean, without contrived activity, everything under heaven is well ordered." Weren't Yao and Shun sages? Weren't the buddhas and enlightened teachers special people? They simply managed to illuminate This Mind.
Therefore, since antiquity, the buddhas and enlightened teachers have never established words and texts as sacred: they just transmitted Mind with Mind, without any other separate teaching. If there is some other teaching outside This Mind, this is a deluded theory, not the words of the Buddha. Thus, when we use the name Mind, it is not the ordinary person's mind that falsely engenders discrimination: rather, it is the silent and motionless Mind in each person.
People cannot preserve this inherent Mind for themselves. Unwittingly they make false moves and are suddenly thrown into confusion by the wind of objects: they are buried in sensory experiences, which arise and disappear again and again. They falsely create the karmic suffering of endless birth and death. Therefore, the buddhas and enlightened teachers and sages appeared in the world by the power of their past bodhisattva vows. They use great compassion and directly point out that the human mind is inherently enlightened, and they enable people to awaken to the mind-buddha.
Your majesty must contemplate his own inherent mind. During lulls in the myriad functions of state, Your Majesty should sit upright in the palace, without thinking of good and evil at all, just like a golden statue of Buddha. Then the false thinking of birth and destruction is totally obliterated and the obliterating is obliterated, in an instant the mindground is quiet and motionless, with nothing to rest on. Body and mind are suddenly empty: it's like leaning on the void. All that appears here is total clarity and illumination.
At this moment you should look carefully at your original face before your father and mother were born. As soon as it is brought up, you awaken to it: then like a person drinking water, you know yourself whether it is cool or warm. It cannot be described or explained to anyone else. It's just a luminous awareness covering heaven and earth.
When the realm I've just talked about spontaneously appears before you, you will have no doubts about birth and death, you will have no doubts about the sayings of the buddhas and enlightened teachers- indeed, you will have met the buddhas and enlightened teachers. This is the wonder transmitted from person to person by buddhas and enlightened teachers since antiquity.
You must make it your concern: be careful not to neglect it. Be like this even when attending to affairs of state and working for the renovation of the people. Use this Path also to be alert to all events and to encourage all our ministers and common subjects to share together in the uncontrived inner truth and enjoy Great Peace. Then the buddhas are sure to rejoice.
- T'aego (1301-1382)
Taken from A Buddha from Korea: The Zen Teachings of T'aego, Thomas Cleary (1988)