《淮南子·齐俗训》
屠牛吐一早晨宰杀九头牛，可是他的刀还是能锋利得可以剃下毛发；庖丁的刀用了十九年，可是刀刃还像刚开过口的新刀一样。
屠牛吐一朝解九牛，而刀以剃毛；庖丁用刀十九年，而刀如新剖硎。
Tu Niu spent a whole morning slaughtering nine cows, but his knife was still sharp enough to shave off hair; Pao Ding's knife was used for nineteen years, but the blade was still as sharp as a new knife that had just been opened.