Mencius - Book 3, Part 1, Chapter 1

When the prince, afterwards duke Wan of T'ang, had to go to Ch'û, he went by way of Sung, and visited Mencius.

Mencius discoursed to him how the nature of man is good, and when speaking, always made laudatory reference to Yâo and Shun.

When the prince was returning from Ch'û, he again visited Mencius. Mencius said to him, 'Prince, do you doubt my words? The path is one, and only one.

'Ch'ang Chi'en said to duke King of Ch'î, "They were men. I am a man. Why should I stand in awe of them?" Yen Yüan said, "What kind of man was Shun? What kind of man am I? He who exerts himself will also become such as he was." Kung-Ming Î said, "King Wan is my teacher. How should the duke of Châu deceive me by those words?"

'Now, T'ang, taking its length with its breadth, will amount, I suppose, to fifty lî. It is small, but still sufficient to make a good State. It is said in the Book of History, "If medicine do not raise a commotion in the patient, his disease will not be cured by it."'
~ James Legge translation via nothingistic.org ~

Go here to read the introductory post to this serialized version of the Works of Mencius.