大般涅槃經疏 22.14

22.14

「爾時光明」下，第二論義，有問答。問意者，若菩薩具修十事，如來何故不修淨土？佛答為四：一我因具十事，眾聖亦然；二「若使世界」下，訶其所問；三「西方」下，示其無勝淨土；四「為化眾生」下，為化眾生出穢土。悉如文。

From "At that time, Bright [Virtue King]..." onward is the second part, debating the meaning, which contains questions and answers. The gist of the question is: if a bodhisattva fully cultivates the ten matters, why does the Tathāgata not cultivate a pure land? The Buddha's answer has four parts: first, "In the causal stage I was equipped with the ten matters, and so were all the sages"; second, from "If this world were to..." onward, he rebukes his question; third, from "In the west..." onward, he shows him the unsurpassable pure land; fourth, from "In order to transform sentient beings..." onward, he appears in an impure land to transform sentient beings. All are as in the text.