《新唐书·列传·卷二十二》
太宗后来临朝，感叹地说： 以铜做镜子，可以端正衣冠；以古史为镜子，可以了解王朝兴废；以贤人做镜子，可以明白治政得失。
帝后临朝叹曰： 以铜为鉴，可正衣寇；以古为鉴，可知兴替；以人为鉴，可明得失。
Taizong later came to the court and said with emotion: One can use a bronze mirror to straighten one's clothes; one can use history as a mirror to understand the rise and fall of a dynasty; one can use the wise and virtuous as a mirror to understand the achievements and failures of governance.