Moreover, when the moment of understanding comes, do not think in terms of understanding, not understanding or not not-understanding, for none of these is something to be grasped. This Dharma of Thusness when ‘grasped' is ‘grasped', but he who ‘grasps' it is no more conscious of having done so than someone ignorant of it is conscious of his failure. Ah, this Dharma of Thusness—until now so few people have come to understand it that it is written: ‘In this world, how few are they who lose their egos!' As for those people who seek to grasp it through the application of some particular principle or by creating a special environment, or through some scripture, or doctrine, or age, or time, or name, or word, or through their six senses—how do they differ from wooden dolls? But if, unexpectedly, one man were to appear, one who formed no concept based on any name or form, I assure you that this man might be sought through world after world, always in vain! His uniqueness would assure him of succeeding to the Patriarch's place and earn for him the name of Śākyamuni's true spiritual son: the conflicting aggregates of his ego-self would have vanished, and he would indeed be the One! Therefore is it written: 'When the King attains to Buddhahood, the princes accordingly leave their home to become monks.' Hard is the meaning of this saying! It is to teach you to refrain from seeking Buddhahood, since any SEARCH is doomed to failure. Some madman shrieking on the mountain-top, on hearing the echo far below, may go to seek it in the valley. But, oh, how vain his search! Once in the valley, he shrieks again and straightway climbs to search among the peaks—why, he may spend a thousand rebirths or ten thousand aeons searching for the source of those sounds by following their echoes! How vainly will he breast the troubled waters of life and death! Far better that you make NO sound, for then will there be no echo—and thus it is with the dwellers in Nirvāņa! No listening, no knowing, no sound, no track, no trace—make yourselves thus and you will be scarcely less than neighbours of Bodhidharma!
Never allow yourselves to mistake outward appearance for reality. Avoid the error of thinking in terms of past, present and future. The past has not gone; the present is a fleeting moment; the future is not yet to come. When you practise mind-control, sit in the proper position, stay perfectly tranquil, and do not permit the least movement of your minds to disturb you. This alone is what is called liberation.
Ah, be diligent! Be diligent! Of a thousand or ten thousand attempting to enter by this Gate, only three or perhaps five pass through. If you are heedless of my warnings, calamity is sure to follow. Therefore is it written:
Exert your strength in THIS life to attain!
Or else incur long aeons of further pain!
-Huang-Po, The Wan Ling Record, John Blofeld translation