history
Final line of Cao Zhi's (曹植) 《七步诗》 (Seven-Pace Poem), Three Kingdoms period. His brother Emperor Cao Pi ordered him to compose a poem within seven paces on pain of death. Cao Zhi produced: 煮豆燃豆萁，豆在釜中泣。本是同根生，相煎何太急 - 'To boil beans they burn the beanstalks; the beans weep in the pot. Born of the same root, why boil each other so fiercely?' Beans and stalks are brothers; the poem shamed Cao Pi into sparing him.
usage
Used almost exclusively between parties who should be allies - family, compatriots, colleagues, former partners. Carries a note of reproach and sadness, not anger.
