無量壽經優婆提舍願生偈註 1.74

1.74

佛本何故起此莊嚴？見有佛土，但是小菩薩，不能於十方世界廣作佛事。或但聲聞人天，所利狹小。是故興願：願我國中有無量大菩薩眾，不動本處遍至十方，種種應化如實修行常作佛事。譬如日在天上而影現百川，日豈來耶？豈不來耶？如《大集經》言「譬如有人善治堤塘，量其所宜，及放水時不加心力」。菩薩亦如是，先治一切諸佛及眾生應供養、應教化種種堤塘，及入三昧身心不動，如實修行常作佛事。如實修行者，雖常修行實無所修行也。是故言安樂國清淨，常轉無垢輪，化佛菩薩日，如須彌住持。

Why did the Buddha originally raise this adornment? He saw that there are Buddha lands that have only minor bodhisattvas who are unable to perform Buddha activities widely in the worlds of the ten directions; or they have only śrāvakas, gods, and humans, so that what they benefit is narrow and small. Therefore he made the vow: "I vow that in my land there shall be an assembly of immeasurable great bodhisattvas who, without moving from their original place, reach everywhere throughout the ten directions, manifesting various responses and transformations, practicing in accordance with reality, and constantly performing Buddha activities." For example, the sun is in the sky yet its reflection appears in a hundred rivers; does the sun come, or does it not come? As the Mahāsaṃnipāta Sūtra states: "For example, someone is skilled at building dikes and embankments, measuring what is appropriate; when releasing the water, he exerts no mental effort." Bodhisattvas are also like this: they first build various embankments of all Buddhas and sentient beings that should be made offerings to or taught and transformed; and when they enter samādhi, with body and mind unmoving, they practice in accordance with reality and constantly perform Buddha activities. "Practicing in accordance with reality" means that although they constantly practice, in reality there is nothing practiced. Therefore it is said: "The Land of Peace and Bliss is pure; / It constantly turns the immaculate wheel. / The sun of the transformed Buddhas and bodhisattvas / Upholds like Mount Sumeru."