What's the use of Duke Zhou's words?

Wang Cheng and Tang Shuyu usually live in seclusion and give a flat leaf to Tang Shuyu as a jade Jue, saying, "I'll seal you with this." Uncle Yu happily told the Duke of Zhou about it, and the Duke of Zhou asked for instructions: "Does the emperor want to seal the danger?" Cheng Wang said, "It's just me joking with Tang Shuyu." Duke Zhou said, "I heard that the son of heaven is not joking." What the emperor said should be recorded by historians, sung by musicians and praised by scholars. "So he sealed it in Jin. Zhou Gongdan can be said to be good at words. In a word, Cheng Wang paid more attention to his speech, showing the meaning of caressing his younger brother and assisting the royal family. In turn, the King of England and Tang Shuyu took a plane tree leaf as a static jade and said to Tang Shuyu, "I use this letter to you." Uncle Yu happily told the Duke of Zhou about it, so Zhou asked the King of Qi for instructions and said, "Can the son of heaven seal Yu?" Wang added, "Su Yu was only joking with Tang himself. The duke said, "I heard that the son of heaven can't tell jokes." . Yes, officials should record, harvest and celebrate. "Then sealed in jin. The Duke of Zhou spoke gently, and paid more attention to saying that he made a statement to become king, to show his love for his brother, and to the royal family.