Present Abbot of Antaiji:
What is zazen, what is practice?"
"Just sitting, just doing."
"For nothing. Just do it. Practice the dharma for the sake of the dharma. There is no goal to reach, nothing to long for and nothing to attain. Just follow life in this one single instant, right here, right now - the life that you are presently living. Be one with reality, that is all."
The theory is really simple. The only problem is that theory alone will not help us to be content with our practice. Although practice of the buddha way is supposed to be the easiest thing in the world, I think it is a fact that we are never quite content with our practice. Why?