Practice does not mean that whatever you do, even lying down, is zazen. When the restrictions you have do not limit you, this is what we mean by practice. When you say, “Whatever I do is Buddha nature, so it doesn’t matter what I do, and there is no need to practice zazen,” that is already a dualistic understanding of our everyday life. If it really does not matter, there is no need for you even to say so. As long as you are concerned about what you do, that is dualistic.
If you are not concerned about what you do, you will not say so. When you sit, you will sit. When you eat, you will eat. That is all. If you say, “It doesn’t matter,” it means that you are making some excuse to do something in your own way with your small mind. It means you are attached to some particular thing or way. That is not what we mean when we say, “Just to sit is enough,” or “Whatever you do is zazen.”
Of course whatever we do is zazen, but if so, there is no need to say it.When you sit, you should just sit without being disturbed by your painful legs or sleepiness. That is zazen. But at first it is very difficult to accept things as they are. You will be annoyed by the feeling you have in your practice.
When you can do everything, whether it is good or bad, without disturbance or without being annoyed by the feeling, that is actually what we mean by “form is form and emptiness is emptiness.
“When you suffer from an illness like cancer, and you realize you cannot live more than two or three years, then seeking something upon which to rely, you may start practice. One person may rely on the help of God. Someone else may start the practice of zazen. His practice will be concentrated on obtaining emptiness of mind. That means he is trying to be free from the suffering of duality.