The second half of a famous couplet in Bai Juyi's (
白居易) Tang poem
《赋得古原草送别》:
离离原上草,一岁一枯荣。野火烧不尽,春风吹又生 - 'Lush grasses on the old plain, each year they wither and flourish. Wildfire cannot burn them off; the spring wind blows and they grow again.' Written when Bai was sixteen.