《孔子家语·六本》
一个人思想感情发生了变化，他敲击的声音也会随之发生变化，所以心意诚恳的感情，能传达到金石制作的乐器上，何况是人呢？ 
其志变者，声亦随之，故至诚感之，通于金石，而况人乎？ 
When a man's thoughts and feelings change, the sounds he makes will also change. Therefore, sincere feelings can be communicated to musical instruments made of metal or stone. How much more so to man?  