Bai Juyi's poem, "Five Words", the third poem, the whole poem: I'll give you a legal doubt, and I wish you luck without drilling a turtle. It takes three days to test the authenticity of jade, and it will take seven years to distinguish wood. In the days of the Duke of Zhou, he was afraid of gossip and paid homage to the throne before Wang Mang usurped the throne. If this man died from the beginning, who would know the truth of his life?

When Duke Zhou helped him become king, he was also afraid of rumors that he had a plot to usurp the throne. In those days, Wang Mang assisted Emperor Ping of the Western Han Dynasty, but before usurping the Han Dynasty, he was humble and courteous, and he was a polite corporal. If Duke Zhou and Wang Mang both died before everyone knew the truth, then no one could know their true character in treating people. This is the story of Duke Zhou and Wang Mang, which shows that what goes around comes around, which needs time to test. We can't judge a person's moral character just by observing his behavior for a short time. It will take a long time to reach a correct conclusion.