During the Eastern Han Dynasty, Du Mi was known for his steady character and upright governance, strictly enforcing the law. He joined the campaign against the eunuch faction, investigating and punishing any crimes committed by their relatives or powerful families. Du Mi also cherished talented individuals, always doing his utmost to help them advance and gain promotions.
One spring, Du Mi was sent on an imperial inspection to Gaomi County, where he discovered a village clerk named Zheng Xuan with extraordinary talent. Recognizing his potential, Du Mi promoted him to a position in the county office and later sponsored his studies at the Imperial Academy. Zheng Xuan went on to become a renowned Confucian scholar and educator of the Eastern Han Dynasty.
Years later, Du Mi retired to his hometown due to old age, but he remained deeply concerned with governance, disregarding personal gain or loss. Whenever he met with the prefect or county magistrate, he would praise and recommend the virtuous without hesitation, and expose the corrupt without mercy.
At the same time, a fellow townsman named Liu Sheng also retired from his post as governor of Shu Commandery and returned home. Liu Sheng's philosophy of life was entirely different from Du Mi's. He shut his doors to visitors, played it safe to protect himself, refrained from involving himself in government affairs, and paid no attention to good people or bad people alike.
Once, Governor Wang Yu said to Du Mi while discussing Liu Sheng, "Many people praise Liu Sheng as a noble and upright scholar. What do you think?"
Du Mi shook his head and said, "I don't think so. After Liu Sheng retired, he ignored worldly affairs, retreated into his shell, and only sought his own safety. He knew of worthy men but did not recommend them to the state, and when he heard of evil deeds, he remained as silent as a cicada in winter. Such irresponsibility toward the country makes him a sinner—how can he be praised as noble and pure?"
Then Du Mi added, "Yet whenever I discover a worthy person, I recommend them to you; when I find a wrongdoer, I expose them to you, enabling you to reward and punish appropriately—isn't that also contributing a small effort to the state?"
After hearing this, Wang Yu was deeply impressed by Du Mi's wisdom and from then on held him in even greater respect.
Later, the idiom "silent as a winter cicada" came to describe someone who dares not speak or express their opinion.
Source: *Book of the Later Han*, "Biography of Du Mi"
Meaning of the Idiom: Later, the Chinese idiom "噤若寒蝉" came to describe how someone who dares not speak or express their opinion.