During the Spring and Autumn period, the small state of Wei, located southeast of the powerful Jin state, was forced into an alliance and endured heavy oppression and exploitation imposed by Jin.
In 503 BCE, Duke Ling of Wei, a ruler determined to break free from Jin's dominance, forged a mutual defense pact with Duke Jing of Qi at Shaze and promptly stopped paying tribute to Jin.
When the state of Wei betrayed Jin and allied with Qi, the Jin ruler was furious. He immediately ordered his minister Zhao Jianzi to assemble the army, preparing to invade Wei and force it back into Jin's fold.
Before launching his campaign against the State of Wei, Zhao Jianzi, a powerful noble of the Jin State, sent his advisor Shi Mo to scout the enemy's situation. He decided that if Wei's internal politics were unstable and its people divided, he would strike immediately; otherwise, he would cancel the invasion and keep his forces at bay.
When Shi Mo arrived in the State of Wei, he discovered that Duke Ling of Wei had already made thorough preparations against a potential invasion from the State of Jin. The duke had dismissed the sycophantic and slanderous minister Mi Zixia, and instead appointed the virtuous and respected minister Qu Boyu as his prime minister, quickly winning the people's hearts.
Duke Ling of Wei, to stir up national indignation, sent Minister Wangsun Jia to announce to the people: "The Jin have ordered that every family with two or more children must send one to Jin as a hostage."
When the people of the Wei state heard this, every household was filled with righteous indignation, harboring deep resentment against the state of Jin.
Duke Ling of Wei deliberately pretended to send a group of royal children to the Jin State, stirring up the people's anger. The people blocked the official road, refusing to let them depart. Wangsun Jia incited, "If we don't send hostages, what will happen when Jin sends troops?"
The people roared, "We are not afraid! If they dare to invade, we will fight them to the end!"
When Shi Mo returned to the state of Jin, he reported the situation to Zhao Jianzi, who then formally canceled the plan to attack the state of Wei.
"The idiom 'hold back one's troops' is often used to describe adopting a wait-and-see attitude without taking action."
Source: *Lüshi Chunqiu*, Chapter "Zhao Lei"
Meaning of the Idiom: Later, the Chinese idiom "按兵不动" came to describe adopting a wait-and-see attitude without taking action.