若能思其所以危则安矣,思其所以乱则治矣,思其所以亡则存矣。
(吴兢《贞观政要·刑法》)
(如果能思考为什么会有危险,国家就安全了;想到为什么会有战乱,国家就太平了;想到为什么会有覆亡,国家就能保存了。)
If one keeps thinking about danger that could emerge, then there can be safety; if one keeps reminding oneself of the possible outbreak of war, then there can be peace; if one keeps thinking about the possible fall of the nation, then the nation can be preserved.
(Wu Jing: Important Political Affairs of the Zhenguan Reign)