阿彌陀經疏 1.20

1.20

主功德中略出二種：一者、光明無量；二者、壽命無量。準此經文釋阿彌陀，此土譯之應云無量。又言成佛已來於今十劫者，為遣疑情。有人疑言：壽雖無量，要有始終，未知今者為始為末？今解言：今既所過唯經十劫，當知今後無量劫住故。

Within the virtue of the host, two kinds are briefly brought forth: first, immeasurable light; second, immeasurable lifespan. Based on this sūtra text, explaining 'Amitābha', when translated into this land it should be called 'Immeasurable'. Furthermore, saying 'since he attained Buddhahood it has been ten kalpas up to the present' is to dispel doubts. Some people doubt and say: 'Although his lifespan is immeasurable, it must have a beginning and an end; is the present known to be the beginning or the end?' It is now explained: Since what has passed at present is only ten kalpas, one should know that from now on he will abide for immeasurable kalpas.