Confucius said: I have five out of ten, but I am determined to learn, standing at thirty, not confused at forty, knowing my destiny at fifty, listening to my ears at sixty, and doing what I want at seventy, not exceeding the rules. You knew your destiny at the age of fifty. "Destiny" is a command from heaven. For example, Liu's Justice quoted Dong Zhongshu's Hanshu as saying: "God's will means fate. Liu's "Theory of Justice" said: "Those who know the destiny, their confidants, are born in vain. Master Gai, when Zhou declined, saints did not last long. When you are 50 years old, you can learn the Book of Changes and know that you have something to do, but it's no big deal to be modest. Then the reason why Heaven gave birth to itself is to live up to itself. Therefore, I have a responsibility to know my own destiny. Life depends on itself, but by heaven, saints dare not resign. Confucius studied Yi, but he knew his own destiny. Although we know the destiny, we may not know it, so we must first believe the holy word to learn it.