During the Spring and Autumn period, Ji Zhou, later known as Duke Dao of Jin, was forced into exile in Luoyang due to political strife. There, the Zhou minister Shan Xianggong took him in and treated him like a honored guest.
Despite his youth, Zhouzi carried himself with remarkable maturity and composure. He stood steadily without a hint of frivolity, read with unwavering focus, listened with respectful attention, and spoke always of loyalty, filial piety, benevolence, and righteousness. In his dealings with others, he was consistently kind and harmonious. Though living in the Zhou domain, he grieved upon hearing of disasters in his homeland of Jin and rejoiced at news of its good fortune. Duke Xiang of Shan observed all this with growing delight, believing Zhouzi had great potential and would one day return to Jin as a worthy ruler. Thus, Duke Xiang treated Zhouzi with ever greater care and affection.
Later, Shan Xianggong fell gravely ill and took to his bed, knowing his end was near. So he called his son Shan Qinggong to his bedside and instructed him:
“I can see that Zhouzi is a remarkably promising young man,” the advisor remarked. “Though living in a foreign land, he never forgets his homeland and constantly worries about its fate. He is very likely to return to the State of Jin and take the throne. The current ruler of Jin is far from virtuous—his moral character is deeply flawed. I believe Zhouzi would be a far more suitable successor. After I am gone, you must take good care of him.”
Dan Qinggong, following his father's dying wish, cared for Zhouzi so well after his father's death that Zhouzi was thoroughly pleased.
Soon after, as predicted, internal turmoil erupted in the state of Jin. Duke Li of Jin, who had long feared losing power and had been sidelining the royal princes, was killed. The Jin ministers then sent envoys to Luoyang to bring back Zhouzi, installing him as the new ruler of Jin.
Later, the idiom "sharing joys and sorrows" came to describe a close relationship where happiness and worries are shared, and fates are intertwined.
Source: *Guoyu*, "Discourses of Zhou"
Meaning of the Idiom: Later, the Chinese idiom "休戚相关" came to describe a close relationship where happiness and worries are shared, and fates are intertwined.