Chapter 21, Part 4C - Chuang Tzu

Confucius said, "Your virtue, Sir, is the very counterpart of Heaven and earth, and yet even you must employ these perfect teachings in order to cultivate your mind. Who, then, even among the fine gentlemen of the past, could have avoided such labors?"

"Not so!" said Lao Tan. "The murmuring of the water is its natural talent, not something that it does deliberately. The Perfect Man stands in the same relationship in virtue. Without cultivating it, he possesses it to such an extent that things cannot draw away from him. It is as natural as the height of heaven, the depth of the earth, the brightness of sun and moon. What is there to be cultivated?"

When Confucius emerged from the interview, he reported what had passed to Yen Hui, saying, "As far as the Way is concerned, I was a mere gnat in the vinegar jar! If the Master hadn't taken off the lid for me, I would never have understood the Great Integrity of Heaven and earth!"
~ Burton Watson translation via Terebess Asia Online ~

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