Zheng Zhong was a renowned Confucian scholar of the Eastern Han Dynasty, deeply learned in classics like the *Book of Changes*, *Mao's Book of Songs*, and the *Rites of Zhou*, earning him great fame among the literati.
During the Jianwu era of Emperor Guangwu of the Han Dynasty, Crown Prince Liu Jiang and Prince of Shanyang Liu Jing, admiring the scholar Zheng Zhong's reputation, sent the emperor's son-in-law, Tiger Guard General Liang Song, with a heavy bribe to win him over. Liang Song presented the gold and said, "The Crown Prince and the Prince hold you in high esteem. Accept this gift and join their service." Zheng Zhong replied, "I cannot betray my principles for wealth. I would rather starve in poverty than serve through bribery." He refused outright, earning him a reputation for integrity that endures as a lesson in moral steadfastness.
Upon learning of Liang Song's purpose, Zheng Zhong refused, saying, "The crown prince is the heir to the throne, and the Prince of Shanyang is a noble vassal. According to regulations, they cannot privately associate with guests. I dare not comply."
When Liang Song saw that Zheng Zhong was so ungrateful for the imperial favor, he threatened him severely. Zheng Zhong, however, remained unyielding and firmly refused with harsh words.
When Liang Song returned and reported this to the Crown Prince and the Prince of Shanyang, both were baffled as to why Zheng Zhong had so firmly refused their gifts. Left with no other choice, they could only drop the matter.
Soon after, Liang Song was dismissed from his post for committing crimes and died in prison. Many who were connected to him also faced punishment. However, Zheng Zhong, having firmly rejected Liang Song's attempts to win him over, was completely unaffected by the scandal.
A few years later, Zheng Zhong entered official service, serving as a cavalry commander before being dispatched as an envoy to the Xiongnu, and later promoted to Governor of Wuwei, where he achieved notable administrative success.
Even while serving as an official, he never abandoned his study of the classics, often lecturing young scholars on various texts and dedicating immense effort to annotating *Zuo's Commentary on the Spring and Autumn Annals*.
Once Zheng Zhong completed his commentary on the *Zuo Commentary to the Spring and Autumn Annals*, it quickly spread among scholars. Around the same time, another classicist, Jia Kui, also published his own commentary on the same text. Both works had their own merits and were equally praised by the academic community.
The most renowned classical scholar of that era was Ma Rong, whose reputation far surpassed that of Zheng Zhong and Jia Kui. He had annotated major works like the *Book of Changes*, *Book of Documents*, *Book of Songs*, *Analects*, and *Laozi*, and after deeply studying the *Zuo Commentary*, he planned to write his own *Annotations on the Zuo Commentary*. However, after carefully reading the works of Zheng Zhong and Jia Kui, Ma Rong remarked, "These two scholars have already thoroughly covered the essential points. There is no need for me to add another commentary."
"Jia Kui's commentary is precise but not broad, while Zheng Zhong's is broad but not precise. If the two were combined, it would be both precise and broad. Since these two commentaries already exist, there is no need for me to write another."
Later, Ma Rong indeed never wrote a commentary on the *Zuo Tradition of the Spring and Autumn Annals*.
The idiom "broad but not deep" is often used to describe someone with wide-ranging knowledge but lacking depth.
Source: *Book of Later Han*, "Biography of Ma Rong"
Meaning of the Idiom: Later, the Chinese idiom "博而不精" came to describe how someone with wide-ranging knowledge but lacking depth.