《新唐书·列传·卷五十七》
 皇帝的美德，没有比接受劝谏更重要的，所以前人说： 木材经过墨线测量加工后就是直材，皇帝听从劝谏就是圣王。 
夫帝王之德，莫盛于纳谏。故曰： 木从绳则正，后从谏则圣。 
The emperor's virtue is not more important than accepting advice, so the ancients said: "When timber is measured and processed with an ink line, it becomes straight material. When the emperor listens to advice, he is a sage king."