树欲静而风不止

shù yù jìng ér fēng bù zhǐ

[the tree wants to remain quiet, but the wind won't stop-class struggle is inevitable in class society] 《韩诗外传》九: "树欲静而风不止, 子欲养而亲不待也。 "比喻事物的客观存在及发展, 是不以人的意志为转移的