Chapter 27, Part 6A - Chuang Tzu

Yang Tzu-chu went south to P'ei, and when he got to Liang, he went out to the edge of the city to greet Lao Tan, who had been traveling west to Chin, and escort him in. Lao Tzu stood in the middle of the road, looked up to heaven, and sighed, saying, "At first I thought that you could be taught, but now I see it's hopeless!"

Yang Tzu-chu made no reply, but when they reached the inn, he fetched a basin of water, a towel, and a comb and, taking off his shoes outside the door of the room, came crawling forward on his knees and said, "Earlier I had hoped to ask you, Sir, what you meant by your remark, but I saw that you were occupied and didn't dare to. Now that you have a free moment, may I ask where my fault lies?"
~ Burton Watson translation via Terebess Asia Online ~

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