以鏡觀面,以道正己
The Mirror for the Face, the Way for the Self
古之人目短於自見,故以鏡觀面;智短於自知,故以道正已。故鏡無見疵之罪,道無明過之惡。目失鏡,則無以正鬚眉;身失道,則無以知迷惑。西門豹之性急,故佩韋以緩已;董安於之心緩,故弦統以自急。故以有餘補不足,以長績短,之謂明主。
The people of antiquity, whose eyes were too short-sighted to see themselves, used mirrors to examine their faces. Their wisdom, too short-sighted for self-knowledge, used the Way to correct themselves. Thus the mirror bears no blame for revealing blemishes, and the Way bears no reproach for exposing faults. Without a mirror, the eyes cannot adjust the beard and brows; without the Way, the person cannot perceive his own confusion.
Ximen Bao was impetuous by nature, so he wore a leather strap on his belt to remind himself to be slow. Dong Anyu was by temperament too deliberate, so he wore a bowstring to urge himself toward urgency.
Thus to supplement deficiency with surplus and to extend the short with the long -- this is what is called an enlightened ruler.
Notes
Ximen Bao (西門豹) was a governor under Marquis Wen of Wei, famous for his decisive action in abolishing human sacrifice at Ye. His leather strap (韋, soft and yielding) served as a physical reminder to temper his impulsiveness.
Dong Anyu (董安於) was a minister of the Zhao house in Jin, known for his cautious temperament. His bowstring (taut and urgent) served as a reminder to be more decisive.
