The basic rule in Chan meditation is: "Let your eyes contemplate your nose; let your nose contemplate your mouth; let your mouth contemplate your mind." This allows us to control the monkey of the mind and rein in the wild horse of our thoughts, so that they stop running outside seeking things. As we sit in the meditation hall, we may not stare left and right, because if we gaze all around, then our mind will wander outside, and we won't be able to investigate Chan. Please pay heed to this point, everyone! The time in a meditation retreat is extremely valuable; you could say that there is not a second to lose. We must seize the time and investigate Chan, because only through this investigation can we attain wisdom.
Cultivators of the Way should not treat their skin-bag of a body as a treasure. Only people who are free of this idea can apply effort in cultivating the Way. If you treat your body as a precious thing, then you will become its slave and serve its whims all day long. Therefore, genuine cultivators treat the body as a "stinking bag of skin" and don't prize it highly. Valuing the body is an obstacle to cultivation. We should merely "borrow the false to cultivate what is true," and see it as just an expedient means.
The biggest taboo in the Chan Hall is sleeping during meditation. Most meditators have two problems: restlessness and torpor. That is, if they aren't indulging in idle thinking, they'll be dozing off. Those who know how to work hard, however, will be concentrating their energy on their inquiry; they will absolutely not be sleeping. And if they can enter samadhi, then that's another story altogether.
Through meditation, you can attain "proper concentration and proper reception," which is samadhi. If you realize this state, then you will be "Thus, thus, unmoving, understanding and perfectly clear." How can you reach this state? You must put in a period of vigorous effort and rid your mind of idle thoughts. Then, "when not even one thought arises, the entire substance comes into view," and you will discover your original face, your fundamental identity.
The key to meditation is to investigate the meditation topic in thought after thought. A saying goes, "After long-term investigation, you will naturally attain enlightenment." Keep searching until "the mountains vanish and the rivers disappear," and the good news will naturally arrive, and you will experience a state "beyond the shadows of the willows and the vivid blossoms." Someone may say, "I've attended so many retreats; why haven't I become enlightened?" It's because you haven't been able to endure all kinds of suffering with only the wish to become enlightened. You should realize enlightenment comes from the accumulation of merit and virtue. In time, your merit and virtue will become full, and you will naturally attain enlightenment. To wish for enlightenment without creating any merit or virtue is simply vain thinking. As it's said, "A warty frog has no hope of tasting the flesh of the great, white swan." It's simply impossible.