Chapter 31, Part I - Chuang Tzu

Confucius looked shamefaced and said, "Please, may I ask what you mean by `the Truth'?"

The stranger said, "By `the Truth' I mean purity and sincerity in their highest degree. He who lacks purity and sincerity cannot move others. Therefore he who forces himself to lament, though he may sound sad, will awaken no grief. He who forces himself to be angry, though he may sound fierce, will arouse no awe. And he who forces himself to be affectionate, though he may smile, will create no air of harmony.

"True sadness need make no sound to awaken grief; true anger need not show itself to arouse awe; true affection need not smile to create harmony. When a man has the Truth within himself, his spirit may move among external things. That is why the Truth is to be prized!
~ Burton Watson translation via Terebess Asia Online ~

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