Now I would like to explain how to use the method of shikantaza. First, your posture should be upright. Do not lean in any direction. Be clear about your posture, because if you practice shikantaza, just sitting, at the very least you should be conscientious about sitting. It is also important to remain relaxed.
Next, be aware of your body, but do not think of it as yourself. Regard your body as a car you drive. You have to handle the car well, but it is not you. If you think of your body as yourself, you will be bothered by pain, itchiness and other vexations. Just take care of the body and be aware of it. The Chinese name for this method can be translated as "just take care of sitting." You have to be mindful of your body as the driver must be mindful of the car, but the car is not the driver.
After a period of time, the body will sit naturally and cause no problems. Now you can begin to pay attention to the mind. If you were eating, your mind should be the "mind of eating," and you would pay attention to that mind. When you are sitting, your mind should be the "mind of sitting." You watch this sitting mind. Two different thoughts alternate: the mind of sitting and the mind, or thought, that watches the mind of sitting
]. First you watch the body sitting with little attention to the mind. When the body drops away, watch the mind. What is the mind? It is the mind of sitting! When your attention dissipates, you will lose awareness of this sitting mind and the sensations of the body will return. Then you should again watch the body sitting. Another possibility is that while you watch the mind you fall into a dull state, like "Being on the dark side of the mountain in a cave inhabited by ghosts." When you become aware of this situation, your bodily sensations return, and you should go back to watching them. Thus these two objects of attention, the body and the mind, are also used alternately.
In the state where you watch the mind, are you aware of the external environment, sound for example? If you want to hear sound, you will, and if you do not want to hear sound, you won't. At this point, you primarily pay attention to your own mind. Although you may hear sounds, they do not create discriminations.
There are three stages in this practice. You should start at the beginning and progress to deeper levels. First be mindful of your body[kayaupasana]. Then be mindful of your mind[vedana, cittaupasana], and of the two thoughts alternating in it.
The third stage is enlightenment. The mind is clear and, as the poem quoted said, "In silence, words are forgotten. In utter clarity, things appear." When you first practice, you will probably be in the first or second level. If you use this method correctly you will not enter into samadhi.
This last point needs clarification. It depends on how we use the term "samadhi." In Buddhadharma, samadhi has many meanings. For instance, Sakyamuni Buddha was always in samadhi. His mind was not moving, yet he still continued to function. This is wisdom. Sakyamuni Buddha's samadhi is great samadhi and this is the same as wisdom. When I said that in the practice of Silent Illumination, you should not enter samadhi, I meant worldly samadhi[trance] where you forget about space and time and are oblivious to the environment. The deeper kind of samadhi, which is the same as wisdom, is in fact the goal of Silent Illumination.http://www.facebook.com/note.php?note_id=241704616435
Shikantaza and Silent Illumination, Master Sheng Yen
And what is right speech? Abstaining from lying, from divisive speech, from abusive speech, & from idle chatter: This is called right speech.