《论语·为政篇》
孔子说： 我十五岁立志于学习；三十岁就有了自己的德行和做人的原则；四十岁遇到事情不再感到困惑；五十岁就知道哪些是不能为人力支配的事情而乐知天命；六十岁能正确对待各种言论，不觉得不能接受；七十岁能随心所欲而不越出规矩。 
子曰： 吾十有五而志于学，三十而立，四十而不惑，五十而知天命，六十而耳顺，七十而从心所欲，不逾矩。 
Confucius said: When I was fifteen, I was determined to study; When I was thirty years old, I had my own virtues and principles of being a human being; When I was forty, I no longer felt confused when I encountered things; When I was fifty years old, I knew what could not be controlled by human beings and was happy to know my destiny; At the age of 60, one can treat various remarks correctly without feeling unacceptable; At the age of seventy, one can do whatever one wants without going beyond the rules.