Do Not Let One Fault Hide Great Merit — One Mistake Is Not the Whole Person

In the thirty-third year of Duke Xi, the Zuo Commentary records that a Qin expedition against Zheng failed and was defeated by Jin at Mount Xiao on its return. When the three commanders, including Mengming, were released and came home, Duke Mu of Qin met them in plain mourning clothes. He admitted that he had ignored Jian Shu’s warning and said, “I will not let one fault obscure great merit.” The word sheng means an error or failing. He was not denying the defeat; he was refusing to let one mistake erase the commanders’ record as a whole.

The line still matters when we judge a colleague, a friend or ourselves. A mistake may require accountability, and a repeated pattern can become reliable evidence. But turning a single event into a lifelong verdict on the whole person may make judgement look decisive without making it more accurate. Fairness is not indulgence. It means keeping the scope of the conclusion proportionate to the evidence.

Source text: https://ctext.org/chun-qiu-zuo-zhuan/xi-gong-san-shi-san-nian/zh