Mencius, known as Meng Ke, was a prominent thinker of the Warring States period and a leading representative of the Confucian school.
During the Warring States period, when constant warfare ravaged the land and rulers oppressed the people, Mencius carried forward Confucius's teachings of benevolence. He championed kingly governance over tyranny, urging feudal lords to adopt humane policies. Traveling with his disciples through Qi, Song, Zou, Lu, Teng, and Liang, Mencius tirelessly spread his political vision.
Mencius advocated for benevolent governance, a vision that resonated with the common people's hopes but proved difficult to implement amid the chaos of warring states.
Once, his student questioned whether promoting "benevolence" was actually useful, and Mencius replied:
Mencius argued, "Benevolence will surely overcome cruelty, just as water will surely extinguish fire—this is beyond doubt. Yet some who practice benevolence are like a man trying to put out a cartload of burning firewood with a single cup of water. When that fails, they conclude that water cannot conquer fire, which only aligns them with the cruel and unkind, and even the small kindness they once had will vanish."
Mencius used the simple analogy that "although a cup of water cannot extinguish a cartload of burning firewood, water can still put out fire" to illustrate that "benevolence will surely overcome cruelty." Yet, despite traveling tirelessly for decades, he was still unable to realize his political ideals among the feudal lords.
Later, the idiom "A Cup of Water for a Cartload of Firewood" came to describe a force too weak to make a difference.
Source: *Mencius*, Chapter "Gaozi I"
Meaning of the Idiom: Later, the Chinese idiom "杯水车薪" came to describe a force too weak to make a difference.