湯 以 伐 桀 ， 而 恐 天 下 言 己 為 貪 也 ， 因 乃 讓 天 下 於 務 光 。 而 恐 務 光 之 受 之 也 ， 乃 使 人 說 務 光 曰 ： 『 湯 殺 君 而 欲 傳 惡 聲 于 子 ， 故 讓 天 下 於 子 。 』 務 光 因 自 投 於 河 。
After Tang attacked Jie, he was afraid every one would say he acted out of greed, and he ceded the imperial throne to Wu Guang. Yet, he was afraid Wu Guang would accept. So he sent someone tell Wu Guang : “Tang has killed his lord, and wants the blame to fall upon you. This is why he offers you the throne.” Because of this Wu Guang threw himself into the Yellow River.
Tang (湯) is Cheng Tang, the founder of the Shang dynasty, Jie (桀) is the tyrant Jie, the last ruler of the Xia (overthrown in 1765 BC according to traditional chronology)
The story of Wu Guang (務 光) cannot be found in history books like the Shangshu or Shiji, but other versions of this story can be found in other pre-Han works.
The Chu Ci number 38 (哀 時 命) mentions the story of Wu Guang : (務 光 自 投 於 深 淵 兮 。 不 獲 世 之 塵 垢 。)
Zhuangzi has, in chapter 28, a different version of this story, in which Cheng Tang asks Wu Guang (among others) for advice before attacking Jie. Wu Guang refuses to help, but points out that Yi Yin (who actually helped Tang to overthrow Jie) is violent enough for this. After, his victory, Tang offers (in good faith according to Zhuangzi) the throne to Wu Guang, who says he would not participate in such a crime, and throws himself in the river.
In both story, Cheng Tang is pictured as a bad man, Han Feizi makes him a little worse.