《庄子·杂篇·列御寇》
施加皮肉之刑的，不外乎是金属或木质的刑具；给内心世界带来惩罚的，则是自身的烦乱和行动的过失。
宵人之离外刑者，金木讯之；离内刑者，阴阳食之。
Those who inflict physical punishment only use metal or wooden instruments of punishment; those who punish the inner world use their own inner turmoil and wrongdoings.