《新唐书·列传·卷二十九》
当时晋州地震不停，高宗询问这事的征兆，张行成回答说： 天，是阳，君主的象征；地，是阴，臣子的象征。
时晋州地震不息，帝问之，对曰： 天，阳也，君象；地，阴也，臣象。
At this time, Jinzhou is afflicted by incessant earthquakes. Gaozong inquires about the significance of this, to which Zhang Xingcheng replies: "Heaven represents the yang and symbolizes the sovereign, while Earth represents the yin and symbolizes the subjects."