Yang Yan of Fengxiang, whose grandfather and father were both renowned for their filial piety and honored by the court, was himself handsome, a brilliant writer, and widely known for filial piety. After Emperor Dezong of Tang ascended the throne, he was selected as chancellor.
When Yang Yan became chancellor, he accomplished several significant deeds for the nation, but he prioritized personal grudges over state interests, earning the resentment of fellow ministers. Serving alongside him was Lu Qi, whom Yang Yan openly disdained for his ugly appearance. Lu Qi, in turn, harbored a deep-seated hatred.
Later, when Yang Yan was dismissed as chancellor and reassigned as Left Deputy Director, Lu Qi seized the opportunity for revenge. Yang Yan had previously owned a private residence in Luoyang, which he entrusted to his trusted subordinate, Zhao Huibo, the governor of Henan, to sell on his behalf. Zhao Huibo then purchased the property himself to use as a government office. After Yang Yan's dismissal, the imperial censors impeached him for "forcing an official to sell his private residence, inflating the price, and collecting excess money." Lu Qi fanned the flames, falsely accusing him of "embezzling public funds, which should be punishable by strangulation." Yang Yan had also angered Emperor Dezong over other matters, and was ultimately exiled to Yazhou. Just a hundred li from his destination, he was ordered to commit suicide.
Later, the idiom "stealing from one's own post" came to describe embezzling public or work-related property under one's management.
Source: *Old Book of Tang*, "Biography of Yang Yan"
Meaning of the Idiom: Later, the Chinese idiom "监守自盗" came to describe embezzling public or work-related property under one's management.