During the Eastern Han Dynasty, Ban Chao was a famous historical figure. His father, Ban Biao, was a renowned Confucian scholar who focused on history in his later years and authored the *Postscripts to the Records of the Grand Historian*; his brother, Ban Gu, compiled the great historical work *Book of Han*; and his sister, Ban Zhao, was also a historian who completed the *Book of Han*. Ban Chao himself initially studied literature, but later threw down his brush to join the army, becoming a celebrated general.
From a young age, Ban Chao harbored grand ambitions. He paid little attention to trivial matters but was deeply filial, often taking on rough and tiring chores at home without shame. With a sharp tongue and a talent for debate, he also read widely across many books.
In 62 AD, during the reign of Emperor Ming of the Han Dynasty, Ban Chao's elder brother Ban Gu was summoned to the capital Luoyang to serve as an imperial librarian, an official in charge of state archives. Ban Chao and his mother moved with him. Due to their family's poverty, Ban Chao often made a living by copying books for the government. One day, weary of his labor, he threw down his brush and sighed, "A man of ambition should follow the example of Zhang Qian, who forged alliances in distant lands and earned a marquis's title. How can I spend my days forever hunched over a writing desk?" Those around him mocked his boastfulness, but Ban Chao replied, "How could a common sparrow understand the soaring ambitions of a swan?" This moment marked his resolve to abandon the pen for the sword, a decision that would later lead him to become a legendary diplomat and military strategist in the Western Regions.
After days of this monotonous work, Ban Chao grew deeply frustrated. One day, unable to continue copying, he threw down his brush and declared, "A true man, even without grand ambitions or strategies, should follow the example of Fu Jiezi and Zhang Qian—venture to the Western Regions, earn merit, and win a noble title. How can I bury myself forever among ink and paper, copying texts for others?"
Those around him mocked his complaints as wishful thinking. Ban Chao remained unmoved and declared firmly, "How can shortsighted fools understand the ambition of a true hero?"
Later, Ban Chao finally joined the military. In 73 AD, Dou Gu, the imperial cavalry commander, was ordered to attack the Xiongnu, and Ban Chao was appointed as acting deputy commander.
Once, Ban Chao was ordered by Dou Gu to lead a military campaign. Near Lake Barkol in modern Xinjiang, his forces encountered the Xiongnu King Huyan's troops. Ban Chao commanded his soldiers to fight bravely, annihilating many enemies.
After this, Ban Chao was dispatched on a mission to the Western Regions, covering what is now western Gansu, Xinjiang, and parts of Central Asia beyond the Pamirs. Through wit and courage, he overcame countless obstacles, securing friendly relations with dozens of kingdoms and severing the Xiongnu's right arm—protecting the Han economy from their raids while boosting cultural and trade exchanges between the Western Regions and the interior. His envoys even reached the Western Sea of Tiaozhi, the modern Persian Gulf. For his extraordinary 31-year service, Emperor He of Han bestowed upon him the title Marquis of Dingyuan.
Later, people summarized this important experience in his life as "Throwing Down the Brush to Join the Army." "Joining the Army" means enlisting in the military. This idiom describes abandoning civilian life for military service, heading to the battlefield to achieve merit for the country.
Source: *Book of the Later Han*, "Biography of Ban Chao"
Meaning of the Idiom: Later, the Chinese idiom "投笔从戎" came to describe abandoning civilian life for military service, heading to the battlefield to achieve merit for the country.