It's from the Six Ancestors Tanjing, which is the meditation of the Six Ancestors Huineng. At first, Shen Xiu sang a poem: "The body is like a bodhi tree, and the heart is like a mirror; Wipe it from time to time to avoid dust. " Shen Xiu's poem has reached a high level, but the sixth ancestor felt that he still didn't fully understand it, so he sang another song for this poem: "Bodhi has no trees, and the mirror is not Taiwan; There was nothing, where did the dust come from? " After singing this poem, everyone realized that the Sixth Ancestor was a sage who gained enlightenment, and it was widely circulated from then on.