佛頂尊勝陀羅尼經教跡義記 2.13

2.13

唐云三世，亦云三界也。解曰：三世者，三時分位假立其名，念念遷流對冶為世。三界者，界別不同即有三界，欲、色、無色，九有情居，欲禪四空趣生有異，受報差別麁細不同，唯佛特尊，故超三界，世相輪轉生滅不停，體若虛空，寧居幻境？

In Chinese, [trai-] means “three times,” and also means “three realms.” Explanation: “Three times” is a nominal designation provisionally established for the three temporal states; moment by moment they shift and flow, functioning as remedy, hence called “times.” “Three realms”: because the realms are different, there are three realms: the desire, form, and formless realms, the nine abodes of sentient beings; their destinies and births across the desire [realm], the dhyānas, and the four formless [attainments] are distinct, and the fruition of retribution they experience differs in coarseness and subtlety. Only the Buddha is uniquely honored, and therefore transcends the three realms. The marks of the world rotate and arise and cease without pause; their nature is like empty space—how could he dwell in an illusory realm?