From Mao Zedong's 1959 poem 《
七律·
到韶山》 (On Returning to Shaoshan). The couplet reads:
为有牺牲多壮志,
敢教日月换新天 — 'Because of sacrifice there is greater resolve; we dare to make sun and moon usher in a new sky.' Written on revisiting his hometown after 32 years.