From
龚自珍《
己亥杂诗·
其五》(Gong Zizhen, Qing dynasty, 1839):
浩荡离愁白日斜,
吟鞭东指即天涯。
落红不是无情物,
化作春泥更护花 (Vast parting sorrow — white sun slanting; a poet's whip points east, already the world's edge. Fallen petals are not unfeeling things — turned to spring mud, they nurture the flowers still). Written when Gong resigned his post; the couplet has become the canonical image of self-sacrificing devotion — teachers, mentors, departing officials.