The disciple Kung-tû said, 'All are equally men, but some are great men, and some are little men; how is this?' Mencius replied, 'Those who follow that part of themselves which is great are great men; those who follow that part which is little are little men.'
Kung-tû pursued, 'All are equally men, but some follow that part of themselves which is great, and some follow that part which is little; how is this?' Mencius answered, 'The senses of hearing and seeing do not think, and are obscured by external things. When one thing comes into contact with another, as a matter of course it leads it away. To the mind belongs the office of thinking. By thinking, it gets the right view of things; by neglecting to think, it fails to do this. These the senses and the mind are what Heaven has given to us. Let a man first stand fast in the supremacy of the nobler part of his constitution, and the inferior part will not be able to take it from him. It is simply this which makes the great man.'~ James Legge translation via nothingistic.org ~
Go here to read the introductory post to this serialized version of the Works of Mencius.