咬定青山不放松

From Qing poet-painter Zheng Xie's (郑燮, better known as 郑板桥) 《竹石》 (Bamboo and Rock): 咬定青山不放松，立根原在破岩中。千磨万击还坚韧，任尔东西南北风 - 'It bites fast to the green mountain and will not let go; its roots are planted in cracked rock. Through a thousand grindings and ten thousand blows it stays unbroken, no matter which way the wind blows.' A symbol of principled perseverance, often cited by Xi Jinping.

Common in political speeches about sticking to policies (reform, anti-corruption, poverty alleviation). Subject is usually the speaker or the country, not the literal 竹 (bamboo) of the poem.