荀子 Xunzi · Chapter 30
Exemplary Conduct
The Sage Cannot Improve Upon Ritual
公輸不能加於繩墨，聖人不能加於禮。禮者，眾人法而不知，聖人法而知之。
Gongshu Ban cannot improve upon the plumb line and ink marker; the sage cannot improve upon ritual. Ritual is what the common people follow without understanding, and what the sage follows with understanding.
Notes
Gongshu Ban (公輸班), also known as Lu Ban, was the legendary master carpenter of ancient China, a symbol of supreme craftsmanship.
The Gentleman Compares His Virtue to Jade
子貢問於孔子曰：「君子之所以貴玉而賤珉者，何也？為夫玉之少而珉之多邪？」孔子曰：「惡！賜！是何言也！夫君子豈多而賤之，少而貴之哉！夫玉者，君子比德焉。溫潤而澤，仁也；栗而理，知也；堅剛而不屈，義也；廉而不劌，行也；折而不撓，勇也；瑕適並見，情也；扣之，其聲清揚而遠聞，其止輟然，辭也。」
Zigong asked Confucius: 'Why does the gentleman esteem jade and despise fine stone? Is it because jade is rare and fine stone is common?' Confucius said: 'What a thing to say, Si! Does the gentleman esteem what is rare and despise what is common? The gentleman compares his virtue to jade. Its warmth, luster, and moisture represent benevolence. Its fine grain and orderly texture represent wisdom. Its hardness and inflexibility represent duty. Its sharpness that does not cut represent proper conduct. Its ability to break but not bend represents courage. Its flaws and excellences both being visible represent sincerity. When struck, its sound is clear, resonant, and carries far, then stops abruptly — this represents propriety of speech.'
Notes
Zigong (子貢, 520-456 BC), personal name Duanmu Si (端木賜), was one of Confucius's most eloquent and successful disciples, renowned for his diplomatic and commercial abilities.