This idiom comes from the historical story of Su Wu, a patriotic hero in the Western Han Dynasty, who was trapped by Xiongnu. During the reign of Emperor Wu of the Han Dynasty, he was bent on solving the security risks brought by Xiongnu in the north, so he sent envoys to Xiongnu, and Su Wu was one of them. In the first year of Tianhan, the Huns took the lead in showing kindness to the Han Dynasty and returned the envoys of the Han Dynasty who had been detained earlier. Seeing this, Emperor Wu of the Han Dynasty was also merciful and sent Su Wu to give gifts to the Huns. Unexpectedly, after Su Wu arrived in Xiongnu, he was involved in a murder plan.

Yue Wang Gou, Yu Chang and others want to rebel. In order to improve the success rate, they plan to kidnap the mother of Hun Khan first. Because he was familiar with John Zhang who went to Xiongnu with Su Wu, he told John Zhang about the plan. However, Zhang Shengze felt that if the plan was successful, it would have advantages and disadvantages for the Han Dynasty, so he didn't remind Khan, and he also sponsored Yu Chang with a lot of money. A month later, Yu Chang and his party took advantage of Khan's going out to launch an attack, but in the end they failed. John Zhang said that he was worried about being implicated, so he told Su Wu what happened before. Su Wu learned that, for fear of offending Khan of the Han Dynasty, he raised his sword and killed himself.

Su Wu was badly injured, but he was finally rescued. After that, Khan persuaded Su Wu many times, but no matter how threatened and seduced by the other party, Su Wu was unmoved. Khan banished him to the barren North Sea only because he was too stubborn, and he stayed there for more than ten years. After Zhao Han ascended the throne, he sent messengers to Xiongnu to beg Su Wu, but Xiongnu lied that Su Wu was dead. However, the messengers of the Han Dynasty who had learned the truth from their population did not take it seriously, but it was difficult to tell the source, so they fabricated the story of the goose passing the book.

The messenger of the Han Dynasty claimed that one day Zhao Han shot down a wild goose from the sky. When the court presented this wild goose to Zhao Di, they found silk tied to its feet. The content of the silk book is that Su Wu is in the North Sea. Xiongnu Khan went his own way, knowing that Su Wu was still alive, and finally had to reluctantly return to Su Wu. After that, people started using it? Hongyan delivers books? This idiom.