During the Southern and Northern Dynasties, Zong Yue, a native of Nanyang, rose from a minor county clerk to a military commander through battlefield exploits, eventually receiving noble titles and imperial gifts from the Liu Song emperor.
Despite his brilliant military achievements, General Zong Yue was notoriously cruel, often killing excessively in battle. When Prince Liu Dan of Jingling rebelled, Zong Yue captured Guangling City, and the emperor ordered all men inside killed. Following the decree, Zong Yue personally joined the slaughter, but before each execution, he would first whip and torture the victim, sometimes targeting their face, all while watching with gleeful delight. In this single massacre, he alone murdered thousands of innocent civilians.
During the reign of the deposed Emperor of Song, whose cruelty and tyranny knew no bounds, he naturally trusted and promoted brutal officials like Zong Yue, using them to massacre court ministers on a grand scale. Zong Yue and his ilk, as if they had finally found a wise ruler who appreciated their talents, devoted themselves heart and soul to his service. Emboldened by these vicious henchmen, the deposed emperor grew even more reckless and unrestrained.
“He who commits many injustices will surely meet his doom.” Later, the deposed emperor was dethroned, and Zong Yue was imprisoned and died in jail. The idiom “exert one’s utmost” is later used to describe putting forth all one’s heart and strength.
Source: *History of the Southern Dynasties*, "Biography of Zong Yue"
Meaning of the Idiom: Later, the Chinese idiom "尽心竭力" came to describe putting forth all one’s heart and strength.