From "Biography of Wei Zhi in Old Tang Dynasty": "My husband can wear bronze mirror clothes; Taking history as a mirror, we can know the rise and fall; Taking people as a mirror, you can understand the gains and losses. "

After Wei Zhi's death, Emperor Taizong cried bitterly. He said: I have three mirrors (they used to be bronze mirrors). "With copper as a mirror, I can dress." I can put on his clothes and hat. "Taking history as a mirror", observing his own administration with history, "knowing the rise and fall", how to make the dynasty prosperous and how to make the dynasty perish, he can observe from history; "Taking the people as a mirror" requires a wise minister to convince him to "know the gains and losses", so that you can understand the gains and losses of all his policies and then correct them. Emperor Taizong said that he had these three mirrors. When Wei Zhi died, one side was broken. It can be seen that a wise monarch must cherish and cherish talents very much in order to win the trust of these ministers.