During the late Spring and Autumn period, Wu She, the Grand Tutor of Chu, was known for his unwavering integrity and was deeply respected by Crown Prince Jian. However, the Junior Tutor Fei Wuji, who served alongside Wu She, was a treacherous schemer whom the prince despised. Fei Wuji harbored a grudge because of this.
In 527 BC, the scheming minister Fei Wuji was sent by King Ping of Chu to the State of Qin to bring back a bride for the crown prince, Jian. Upon his return, Fei Wuji reported to the king, "The bride is breathtakingly beautiful—Your Majesty should keep her for yourself and find another woman for the prince." The lustful King Ping, unable to resist, took his son's bride as his own.
From then on, King Ping gradually distanced himself from the crown prince, sending him to guard a remote border pass. Fei Wuji seized the opportunity to slander the prince, claiming he was plotting rebellion, and urged the king to arrest Wu She. After Wu She was imprisoned, Fei Wuji pressed the king to lure Wu She's two sons, Wu Shang and Wu Zixu, to their deaths. Wu Shang fell for the trap and was killed alongside his father, but Wu Zixu escaped to the state of Wu.
At that time, Prince Guang of Wu was on the lookout for talent, plotting to seize the throne. Wu Zixu, a man of exceptional ability, became Prince Guang's trusted confidant. Wu Zixu recommended a brave warrior, who helped Prince Guang assassinate King Liao of Wu, allowing Prince Guang to become the ruler of Wu, historically known as King Helü of Wu.
The King of Wu was deeply grateful to Wu Zixu, appointing him as a high minister and consulting him on all military and state affairs. Wu Zixu, in turn, devoted himself to strengthening the kingdom and preparing for an invasion of Chu to avenge his father and brother.
In 515 BCE, Chu State's Left Minister Xi Wan was deeply beloved by the people, which sparked the jealousy of Fei Wuji, who then schemed to have Xi Wan and his entire family executed.
Bo Pi, a relative of Xi Wan, heard of his kinsman's murder and fled that very night
King Helü of Wu was discussing plans to attack Chu with Wu Zixu when he heard that Bo Pi had arrived. He invited Bo Pi into the palace and hosted a banquet in his honor. During the meal, Bo Pi recounted his misfortunes in Chu, and Wu Zixu showed deep sympathy. At this, the attending minister Bei Li quietly asked Wu Zixu, "We still don't know what kind of person Bo Pi truly is—why do you trust him so readily at first sight?"
Wu Zixu said solemnly, "It is because our grievances are the same. Have you not heard the 'Song of the River'? Its message is that those who share an illness should pity each other, and those who share a sorrow should rescue each other. How could I not treat with all my heart someone who shares the same fate as me?"
Wu Zixu and Bo Pi became friends at first sight, bonding instantly
Later, people used the idiom "Those Who Share the Same Ills Sympathize with Each Other" to describe mutual sympathy among those with similar experiences.
Source: *Wu Yue Spring and Autumn Annals*, Chapter "Inner Biography of Helü"
Meaning of the Idiom: Later, the Chinese idiom "同病相怜" came to describe mutual sympathy among those with similar experiences.