常玉不瑑,不成文章;君子不学,不成其德。· A piece of jade does not reveal flowery patterns without being engraved; a gentleman can not perfect his virtues without learning.
· A piece of jade does not reveal its patterns until it is carved;a person can not become a man of virtue unless he learns and cultivate himself.
(Dong Zhongshu [179 - 104 BC]: “Policies for Recommending Men of Virtue [Ⅱ]”,collected in History of Han)