From Sima Qian’s (
司马迁) Han-dynasty
《报任安书》 (Letter to Ren An). The full line is
人固有一死,
或重于泰山,
或轻于鸿毛 "everyone must die, but some deaths are weightier than Mount Tai, and some lighter than a goose feather." Sima wrote it while enduring palace castration rather than suicide, explaining why he had to live to finish the
《史记》 (Records of the Grand Historian).