Chapter 2, Part 1A - Chuang Tzu

Nan-kwo Tsze-khî was seated, leaning forward on his stool. He was looking up to heaven and breathed gently, seeming to be in a trance, and to have lost all consciousness of any companion. (His disciple),

Yen Khang Tsze-yû, who was in attendance and standing before him, said, 'What is this? Can the body be made to become thus like a withered tree, and the mind to become like slaked lime? His appearance as he leans forward on the stool to-day is such as I never saw him have before in the same position.'

Tsze-khî said, 'Yen, you do well to ask such a question, I had just now lost myself; but how should you understand it? You may have heard the notes of Man, but have not heard those of Earth; you may have heard the notes of Earth, but have not heard those of Heaven.'
~ James Legge translation via Stephen R. McIntyre ~

Go here to read the introductory post to the chapters of the Book of Chuang Tzu.