During the Spring and Autumn period, after the death of Duke Huan of Qi, the regional hegemon of the Central Plains, his son Duke Xiao of Qi ascended the throne.
In the summer of 634 BCE, a severe famine struck the State of Lu. Seizing the moment, Duke Xiao of Qi personally led a massive army eastward to attack Lu. Duke Xi of Lu, knowing his forces were no match for the Qi army, sent his minister Zhan Xi with cattle, sheep, wine, and food to feast the Qi troops.
At this time, Duke Xiao of Qi's army had not yet entered Lu's territory. Zhan Xi traveled day and night and met Duke Xiao of Qi at the Qi-Lu border. Zhan Xi said to Duke Xiao of Qi:
“We, the people of Lu, have heard that Your Majesty has personally come to our state, so our ruler has specially sent me to offer comfort to your army,” said Zhan Xi, the envoy of Lu. “Are you people of Lu afraid?” sneered Duke Xiao of Qi arrogantly. Zhan Xi, a skilled diplomat, replied with composure, “Those without foresight may be somewhat afraid, but our ruler and ministers are not afraid at all.” Duke Xiao scoffed, “Your state’s treasury is empty, your people’s granaries are bare, and there’s not even grass in the fields—what makes you think you have no reason to fear?”
Zhan Xi, completely composed, replied unhurriedly, "Our reliance is on the decree of King Cheng of Zhou. Long ago, our Lu state's ancestor, the Duke of Zhou, and your Qi state's ancestor, Jiang Taigong, served King Cheng with unwavering loyalty and concerted effort, governing the realm with such dedication that they forgot to eat or sleep, ultimately bringing great peace to the land. King Cheng was deeply grateful to them, had them swear a covenant, and commanded all future generations to remain friendly forever and never harm each other—this is all documented. Our ancestors were so amicable; how could you, Great King, rashly abandon their covenant and attack our Lu state? It is precisely on this foundation that we are not afraid."
Impressed by Zhan Xi's reasoning, Duke Xiao of Qi abandoned his invasion plans and withdrew his troops.
Later, the idiom "You Shi Wu Kong" (Having Support, No Fear) describes being emboldened by reliance on something, acting without scruples or fear.
Source: *Zuo Zhuan*, Chapter "The Twenty-Sixth Year of Duke Xi"
Meaning of the Idiom: Later, the Chinese idiom "有恃无恐" came to describe being emboldened by reliance on something, acting without scruples or fear.