以古为鉴 Learn from history
Explanation
以历史上的成功或失败经验为借鉴，吸取教训，引以为戒。
To use the successes or failures of history as a reference, learn from them, and take warning.
Origin Story
话说唐太宗李世民，雄才大略，励精图治，使大唐盛世空前繁荣。但他并非生来就是明君，年轻时也曾经历过兄弟相残的残酷战争。玄武门之变后，他深感兄弟阋墙的悲剧，痛定思痛，决心以史为鉴，避免重蹈覆辙。他广纳贤才，虚心纳谏，尤其重用魏征，魏征敢于直言进谏，李世民也能够虚怀若谷，采纳建议，从而避免了许多错误。李世民经常告诫自己和臣子们要以史为鉴，要从历史的兴衰成败中吸取教训，避免犯同样的错误。他常说：“以铜为镜，可以正衣冠；以古为镜，可以知兴替；以人为镜，可以明得失。” 他将这句名言刻在宫殿里，提醒自己和臣子们要时刻引以为戒。 正是因为他能够以史为鉴，虚心学习，不断改进，大唐才能在贞观年间达到空前繁荣的盛世景象。
It is said that Emperor Taizong Li Shimin of the Tang Dynasty was a man of great talent and strategy. He worked hard to govern well, and the prosperous Tang Dynasty flourished unprecedentedly under his rule. However, he was not born a wise emperor; in his youth, he had also experienced the cruel war of fratricide. After the Xuanwu Gate Incident, he deeply felt the tragedy of fratricide and decided to learn from history and avoid repeating the same mistakes. He widely recruited talents and humbly accepted advice, especially valuing Wei Zheng, who dared to speak frankly. Emperor Taizong was able to be humble and accept suggestions, thus avoiding many mistakes.
Usage
用于劝诫人们要从历史中吸取教训，避免重蹈覆辙。
Used to warn people to learn from history and avoid repeating past mistakes.
Examples
-
我们应该以史为鉴，避免重蹈覆辙。
wǒmen yīnggāi yǐ shǐ wéi jiàn, bìmiǎn chóngdǎo fùzhé
We should learn from history and avoid repeating past mistakes.
-
古人云：以古为鉴，可以知兴替。
gǔrén yún: yǐ gǔ wéi jiàn, kěyǐ zhī xīngtì
The ancients said: Learn from history, and you can know the rise and fall of dynasties..