"A sword with a sweet mouth and a belly" is an idiom in Chinese, which comes from Sima Guang's "Tongzhi Sword in the First Year of Tianbao in Xuanzong of Tang Dynasty" in the Northern Song Dynasty.
This idiom describes a person who speaks sweet words, but has a sinister heart and wants to frame people everywhere. Its own structure is joint, and it can be used as predicate and attribute in derogatory sentences.
"The sword in the honey" is a sharp weapon for Li officialdom to climb up. Anyone who has talent, merit and reputation is bound to be suppressed by Li. With this skill, he stayed in the position of prime minister for a long time, which caused immeasurable losses to the court and the country.
This reflects the rule of Xuanzong in the late Tang Dynasty. Li's final fate also illustrates the truth that "grievances have a head and are dying."