What is the sound of one hand clapping.
To know that one knows what one knows and to know that one doesnt know what one doesnt know there lies true wisdom.
Knowing it does not compare with loving it; loving it does not compare with delighting in it.
If there were one word that could act as a standard of conduct for one's entire life, perhaps it would be 'thoughtfulness.
If you think in terms of a year, plant a seed; if in terms of ten years, plant trees; if in terms of 100 years, teach the people.