“The Three Worlds refers to the world of desire, the world of form, and the formless world. Living beings within the world of desire still have desire—greed and lust. Living beings within the world of form do not have such intense desire; however, they still have a physical form and appearance. They are still attached to appearances, and therefore, they are not apart from the marks of self, others, living beings, and lifespans. Living beings of the formless realm are without form or shape, yet they still have consciousness, and they are attached to that consciousness.

“Because living beings within these three worlds are still attached, they cannot get out. Only those who have been certified as having attained the fourth stage of Arhatship can completely escape."(TT 47)

三界