阿彌陀經要解 1.75

1.75

猶云彼佛及其人民壽命皆無量無邊阿僧祇劫，蓋西域每用倒文故也。心性照而常寂故為壽命，今徹證心性無量之體，故壽命無量也。法身壽命無始無終故無量，報身壽命有始無終故無量。此亦佛佛道同，皆可名無量壽。應身則隨願隨機延促不等。今以法藏比丘四十八願曾有佛壽無量及人民壽命亦無量之願故，今果成亦如先願，別名無量壽也。此則實有限量，特以人天莫數，名無量耳。然三身既不一異，則應身亦可即是無量之無量矣。

This is equivalent to saying that the lifespans of that Buddha and his people are all measureless and boundless asaṃkhyeya kalpas, for the Western Regions often use inverted syntax. The nature of the mind illumines yet is constantly quiescent, which is why it is lifespan; now, having thoroughly realized the measureless essence of the nature of the mind, his lifespan is therefore measureless. The lifespan of the dharmakāya has neither beginning nor end, and is therefore measureless; the lifespan of the saṃbhogakāya has a beginning but no end, and is therefore measureless. In this too, all Buddhas share the same path, and all can be named 'Measureless Life'. As for the nirmāṇakāya, it varies in length and shortness according to vows and capacities. Now, because among the forty-eight vows of the bhikṣu Dharmākara there were vows that the Buddha's lifespan would be measureless and that the lifespan of his people would also be measureless, now that the fruit is accomplished it is also as formerly vowed, and he is specifically named 'Measureless Life'. This, in fact, has a limit; it is called 'measureless' simply because humans and devas cannot calculate it. However, since the three bodies are neither one nor different, the nirmāṇakāya may also be immediately identified with the measureless of measureless.