阿彌陀經疏 1.184

1.184

經曰：「彼佛國土無三惡趣」，次釋第三答也。彼國實無三惡趣故。所以無者，由阿彌陀佛昔發願言：「設我得佛，國有三惡趣者，亦不取正覺」，乃至「國中天人壽終之後，復更生三惡道者，亦不取正覺」，故知無也。

The sūtra says: "In that Buddha land there are no three bad destinies." Next, the third [part] explains the answer, because in that land there are genuinely no three bad destinies. The reason they do not exist is that Amitābha Buddha made a vow in the past, saying: "If, when I attain buddhahood, there should be the three bad destinies in my land, may I not attain correct awakening," up to, "If, after the devas and humans in my land end their lives, they should again be reborn in the three bad paths, may I not attain correct awakening." Therefore, we know they do not exist.