"Three Thousand Worlds" refers to the three thousand worlds of heaven, earth and hell in Buddhism, representing the whole universe.
"Rolling the world of mortals" refers to the prosperity and vulgarity in the world. No matter in which world, there are birth, old age, illness and death. Everything in the world of mortals is short-lived, and it is futile to cling to these things too much.
This poem expresses the impermanence of life and the thought of transcending the world, reminding people to cherish the present, not to pursue worldly material and desires excessively, but to pursue the inner truth.