力不从心 — “To feel one's strength unequal to one's will”

The idiom "力不从心" (lì bù cóng xīn) originates from "The Book of the Later Han" (《后汉书》), specifically from the biography of Ban Chao. The text states: "如有卒暴，超之气力，不能从心" (Should there be any sudden violence, Ban Chao's strength would not be able to follow his will).

During the Eastern Han Dynasty, Ban Chao was dispatched by Emperor Ming to the Western Regions with a small contingent of soldiers. He achieved numerous successes there. However, after serving for 27 years, Ban Chao had grown old and frail. Yearning for home, he wrote a letter to his son, asking him to deliver it to Emperor He Liu Zhao, requesting to be recalled. When there was no immediate response, his younger sister, Ban Zhao, also submitted a memorial to the emperor, reiterating her brother's plea.

In her letter, she wrote, "Among those who went to the Western Regions with Ban Chao, he is the oldest, now past sixty. He is weak and ill, his hair has turned white, his hands are no longer agile, his ears are deaf, his eyes dim, and he needs a cane to walk... Should any unexpected rebellion occur, Ban Chao's strength would not be equal to his will. This would, on the one hand, harm the long-term stability of the state, and on the other, ruin the hard-won achievements of a loyal minister. It would truly be heartbreaking!"

Emperor He Liu Zhao was deeply moved by her words and immediately issued an edict to recall Ban Chao to the capital. Less than a month after Ban Chao returned to Luoyang, he passed away from an aggravated chest illness, at the age of 71. This story perfectly illustrates the meaning of "力不从心," highlighting a situation where one's desire or intention is strong, but their physical or mental capacity is insufficient to achieve it.