During the Spring and Autumn period, Duke Wen of Jin, Chong'er, ended his years of exile with the help of the state of Qin and returned to Jin to take the throne.
To repay those loyal ministers who had shared hardships and exile with him, Chong'er ordered generous rewards. Fearing omissions, he issued a decree at the city gate: "If anyone's merits have been overlooked, they may come forward."
During the years of exile, a loyal follower named Jie Zitui cared for the future Duke Wen of Jin with unwavering devotion. When starvation threatened, Jie Zitui even cut flesh from his own thigh to make soup for his starving master. Yet when the duke returned to power and rewarded his supporters, Jie Zitui was overlooked.
Yet now, Duke Wen of Jin had not granted Jie Zitui any official position or reward. Jie Zitui, a man of great integrity, harbored no resentment over not receiving recognition from Chong'er. He never mentioned seeking rewards to anyone, believing instead that he did not deserve any compensation at all.
After Chong'er returned to his country, Jie Zitui feigned illness, went home to care for his elderly mother, preferring to make a living weaving straw sandals rather than seeking rank or salary. His mother said to him, "You followed the Marquis of Jin in exile for a full nineteen years; even without merit, you have endured hardship—why not go see the Marquis of Jin?"
Jie Zitui replied calmly, "Among the nine sons of Duke Xian of Jin, our lord Chong'er was the most virtuous. His ascension to the throne was Heaven's will. Yet those who followed him claim it as their own merit—isn't that deception? A thief who steals another's property is a robber, but those who seek rewards from the Duke by claiming Heaven's work as their own are even more shameless. I would rather weave straw sandals for life than fight for such credit."
Seeing her son Jie Zitui maintain such unwavering integrity, his mother willingly joined him in seclusion deep within the mountains. So Jie Zitui took his mother and retreated to Mianshang, in what is now northwest Qinyuan, Shanxi.
When Emperor Wen of Jin learned that Jie Zitui had retreated to Mount Mian, he was filled with regret. He personally searched the mountain but found no trace of Jie Zitui or his mother, so he could only designate Mount Mian as Jie Zitui's nominal fief.
Later, people used the idiom "Claiming Heaven's Credit" to refer to taking credit for others' achievements.
Source: *Zuo Zhuan*, "The Twenty-Fourth Year of Duke Xi"
Meaning of the Idiom: Later, the Chinese idiom "贪天之功" came to describe how taking credit for others' achievements.