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, then it goes beyond the abilities of the samadhi of the spiritual powers of the wisdoms numerous as the dusts in the buddha-lands: it is at once hidden and manifest, sovereign and free in all directions, with great spiritual powers. 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.