Huang Po said to me: All the Buddhas and all sentient beings are nothing but the One Mind, beside which nothing exists. This Mind, which is without beginning, is unborn and indestructible.
It is not green nor yellow, and has neither form nor appearance. It does not belong to the categories of things which exist or do not exist, nor can it be thought of in terms of new or old. It is neither long nor short, big nor small, for it transcends all limits, measure, names, traces and comparisons. It is that which you see before you – begin to reason about it and you at once fall into error.
It is like the boundless void which cannot be fathomed or measured. The One Mind alone is the Buddha, and there is no distinction between the Buddha and sentient things, but that sentient beings are attached to forms and so seek externally for Buddhahood. By their very seeking they lose it, for that is using the Buddha to seek for the Buddha and using mind to grasp Mind.
Even though they do their utmost for a full aeon, they will not be able to attain it. They do not know that, if they put a stop to conceptual thought and forget their anxiety, the Buddha will appear before them, for this Mind is the Buddha and the Buddha is all living beings. It is not the less for being manifested in ordinary beings, nor is it greater for being manifest in the Buddhas.
P’ei Hsiu quoting Huang Po