During the Warring States period, King Kuai of Yan reformed his government and abdicated the throne to his prime minister, Zizhi. General Shibei and Prince Ping, refusing to accept this, raised an army to attack Zizhi, sparking a civil war.
During the Warring States period, chaos erupted in the state of Yan. Seeing an opportunity, King Xuan of Qi sent his general Kuang Zhang with 100,000 troops to invade. The Yan people, weary of civil strife, offered no resistance—soldiers refused to fight, city gates stood open, and locals even welcomed the Qi army with food and drink. Kuang Zhang conquered the Yan capital in just fifty days. But he failed to discipline his troops, who plundered and bullied the people. Soon, the Yan populace rose in rebellion against their occupiers.
At this point, King Xuan of Qi sought advice from Mencius, who was traveling in Qi, asking, "Some advise me not to annex Yan, others urge me to do so—what should I do?"
Mencius replied, "If annexing Yan brings joy to its people, then annex it. There is precedent for this—King Wu of Zhou." This refers to King Wu's campaign against King Zhou of Shang, rescuing the people from misery and establishing the Western Zhou dynasty.
“If annexing the State of Yan does not please its people,” Mencius continued, “then do not annex it. There is a precedent from antiquity—King Wen of Zhou.” This referred to King Wen, father of King Wu, who, despite already possessing two-thirds of the realm, chose to serve the Shang dynasty rather than hasten its downfall, believing the people’s loyalty was not yet exhausted.
Mencius then cited these examples and pointed out, "When the Qi army first invaded Yan, the people of Yan brought food and water to welcome them because they wanted to escape their suffering. But if Qi now annexes Yan, bringing the disaster of national subjugation and plunging them into even greater misery, they will surely turn to hope for rescue from another state!"
King Xuan of Qi paid little heed to Mencius's counsel, fixated instead on annexing the state of Yan. This ambition backfired, sparking rebellion among Yan's people and prompting neighboring states to pledge aid to Yan and attack Qi. Forced to yield, King Xuan of Qi withdrew his troops from Yan.
Later, the idiom "deep water and scorching fire" came to describe people living in extreme misery.
Source: *Mencius*, Chapter "King Hui of Liang"
Meaning of the Idiom: Later, the Chinese idiom "水深火热" came to describe people living in extreme misery.