贤主愈大愈惧，愈强愈恐。故贤主于安思危，于达思穷，于得思丧。《周书》曰：“若临深渊，若履薄冰。”以言慎事也。 --《吕氏春秋-慎大》【註2】

For a wise king, the bigger and stronger his country grows, the more worried he becomes. So the wise king considers how to overcome crisis while in times of peace, how to deal with poverty while the country enjoys prosperity, how to stop losses while he is gaining a lot. The 《Book of Zhou》 says, "We should govern the country as if approaching an abyss or treading on thin ice of a deep river". It means one should be extremely cautious and prudent in dealing with worldly matters. 

【註1】見《君子敬以直内》【註1】

【註2】《呂氏春秋》，又稱《呂览》，战國時代末期的一部政治理论散文的彙編，共26卷，160篇，完成於秦王政六年（公元前241年），為秦国相国吕不韦主持，召集門客各派學者編纂而成。 《吕氏春秋》内容涉及甚广，以道家黃老思想为主，兼收儒、名、法、墨、农和阴阳各先秦諸子百家言論，是杂家的代表作，也是中国古代类书的起源。