《北史·列传·卷四十六》
武帝说 ：管叔、蔡叔虽然也是武王的兄弟，却因反叛被杀戮；而周公旦却辅助成王建立国家，人心各不相同，就像人的脸面互不雷同。
帝曰： 管、蔡为戮，周公作辅，人心不同，有如其面。
Emperor Wu said: The Dukes of Guan and Cai were also King Wu's brothers, but they were executed for their rebellion. However, the Duke of Zhou helped King Cheng establish the state; the hearts of men are different from one another, just as their faces never match perfectly.