怙恶不悛 — “To obstinately persist in evil and refuse to repent or reform”

During the late Western Jin Dynasty, China plunged into chaos, leading to the Sixteen Kingdoms period where various ethnic groups established independent regimes in the north. Liu Cong, a Xiongnu leader, seized power from Han Liu Yuan to establish the Former Zhao dynasty, making Chang'an his capital and wielding great influence. At the same time, Shi Le, a Jie ethnic general who started as a peddler, joined Liu Yuan's army and distinguished himself through military achievements. He harbored resentment towards Liu Cong's usurpation and sought to replace him. After several battles, Shi Le significantly weakened Liu Cong's military strength.

Liu Cong then changed his strategy to win over Shi Le, sending his confidant Guo Si as an envoy to offer Shi Le the title of Grand Tutor, Grand General, King of Zhao, along with twenty subordinate tribes, splendid carriages, divine horses, and a queen for his wife.

However, Cao Ping, a former aide of Shi Le who was now a strategist under Liu Cong, warned his master: "Shi Le's envoys, Wang Xiu and others, are ostensibly here to offer thanks, but in reality, they are assessing the strengths and weaknesses of our territories to prepare for an attack." Liu Cong was furious. Upon Guo Si's return, he immediately executed Wang Xiu and revoked all titles bestowed upon Shi Le.

Infuriated by this betrayal, Shi Le ordered the execution of Cao Ping's entire clan. He then gathered his ministers and declared, "We sent envoys with sincere intentions to restore good relations, but Liu Cong, persisting in his evil ways ('长恶不悛'), not only refused to repent but also murdered our sincere representatives. This is an unforgivable act of extreme wickedness! Therefore, I have decided to seize the Zhao territory and declare myself king."

Consequently, Shi Le established various official positions, built the Zhengyang Gate, and formally declared himself king. In 318 AD, Shi Le killed Liu Cong and established the Later Zhao regime. The phrase "长恶不悛" was later extended to "怙恶不悛," used to describe those who persist in their evil deeds and refuse to reform.