beware of the harm done by small things
It is a Chinese idiom. Pinyin is f à ngch à iy à UD ú, which means to describe some characters whose status is low but can harm others. It comes from Zuo Zhuan, the 22nd year of Duke Fu.
The origin of Idioms
Zuo Zhuan, the 22nd year of the Duke of Fu, said, "you are meaningless. You are small, but you are poisonous. What about the state?"
Idiom usage
Wen Qing was a little impatient here. When she was about to have an attack, she was afraid that the bee might be poisonous and cause trouble, so she had to take her head and swallow it. The 24th chapter of Zeng Pu's Nie Hai Hua in Qing Dynasty
beware of the harm done by small things
There is a mirror in the chest - xiōng yǒu xuán jìng
lay down one 's life for justice - shì shēng qǔ yì