俱舍論疏 12.97

12.97

論「有說餘界至餘亦應爾」，述有部等計。一佛普於一切十方皆能教化，故唯一佛無二三等。若於一處有情難化佛不能化，餘佛於中亦不能化，故無多佛。

On the Śāstra's words, "Some say that in other realms ... the others should also be like this": This sets forth the assertion of the Sarvāstivādins and others. A single Buddha can universally teach throughout all ten directions, so there is only one Buddha and not two, three, or more. If in a single place sentient beings are difficult to transform and a Buddha cannot transform them, other Buddhas would also be unable to transform them therein; hence there are no multiple Buddhas.