觀無量壽佛經義疏 2.54

2.54

「『如此三事，名為淨業。』佛告韋提希：『汝今知不？此三種業，過去未來現在三世諸佛淨業正因。』」三世果德籍此而成，故曰正因。二、明正觀，四：初、勅聽示說；二、讚請；三、勸囑；四、示法。初、勅聽示說。

"'These three matters are called pure karma.' The Buddha told Vaidehī: 'Do you know now? These three kinds of karma are the correct causes for the pure karma of all Buddhas of the three times—past, future, and present.'" The fruitional virtues of the three times are accomplished by relying on these; hence they are called "the correct causes". Second, clarifying the correct contemplation, has four parts: first, commanding to listen and indicating the exposition; second, praising the request; third, exhorting and entrusting; fourth, showing the method. First, commanding to listen and indicating the exposition.