"The most difficult thing is always to keep your beginner's mind. There is no need to have a deep understanding of Zen. Even though you read much Zen literature, you must read each sentence with a fresh mind. You should not say, "I know what Zen is," or "I have attained enlightenment." This is also the real secret of the arts: always be a beginner. Be very very careful about this point. If you start to practice zazen, you will begin to appreciate your beginner's mind. It is the secret of Zen practice."
Zen Mind, Beginner's Mind