《吴子·论将》
吴子说：鼙鼓金铎，是用来指挥军队的听觉号令。旌旗麾帜，是用来指挥军队的视觉号令。禁令刑罚，是用未约束全军的法纪。
吴子曰： 夫鼙鼓金铎，所以威耳；旌旗麾帜，所以威目；禁令刑罚，所以威心。
Wu Zi said: Drums and gongs are used to command the army's auditory signals. Flags and banners are used to command the army's visual signals. Prohibitions and punishments are used to constrain the army's discipline.