觀無量壽佛經疏 2.10

2.10

初、言一時者，正明起化之時。佛將說法，先託於時處。但以眾生開悟，必藉因緣。化主臨機，待於時處。又言一時者，或就日夜十二時，年月四時等。此皆是如來應機攝化時也。言處者，隨彼所宜，如來說法。或在山林處，或在王宮聚落處，或在曠野塚間處，或在多少人天處，或在聲聞菩薩處，或在八部人天王等處，或在純凡若多一二處，或在純聖若多一二處。隨其時處，如來觀知不增不減，隨緣授法，各益所資。斯乃洪鐘雖響，必待扣而方鳴。大聖垂慈，必待請而當說。故名一時也。又一時者。阿闍世正起逆時，佛在何處？當此一時，如來獨與二眾在彼耆闍。此即以下形上意也。故曰一時。又言一時者，佛與二眾於一時中在彼耆闍，即聞阿闍世起此惡逆因緣。此即以上形下意也。故曰一時。

First, regarding "at one time": this directly clarifies the time when transformation was initiated. When the Buddha is about to preach the Dharma, he first depends upon the time and place. It is only because sentient beings' awakening necessarily relies on causes and conditions; the master of transformation approaches their capacities, awaiting the time and place. Furthermore, saying "at one time" refers either to the twelve double-hours of day and night, or the four seasons of the year, and so on. These are all the times when the Tathāgata adapts to capacities to gather and transform. Regarding the "place": according to what is suitable for them, the Tathāgata preaches the Dharma. It may be in mountains and forests, in royal palaces and villages, in wildernesses and charnel grounds, in places with many or few humans and gods, in places with śrāvakas and bodhisattvas, in places with the eight classes of beings, humans, and deva kings, in places of purely ordinary beings or with one or two more, or in places of purely noble ones or with one or two more. According to the time and place, the Tathāgata contemplates and knows them without increase or decrease, conferring the Dharma according to conditions so that each benefits from what sustains them. This is like a great bell: though resonant, it must await striking before it sounds; the Great Sage extends compassion, yet must await entreaty before he preaches. Hence it is called "at one time". Furthermore, "at one time": when Ajātaśatru was instigating rebellion, where was the Buddha? Just at this one time, the Tathāgata was alone with the two assemblies on Mount Gṛdhrakūṭa. This means shaping the upper by means of the lower; hence it says "at one time". Furthermore, "at one time": the Buddha and the two assemblies were at that one time on Mount Gṛdhrakūṭa when they heard the causes and conditions of Ajātaśatru committing this wicked rebellion. This means shaping the lower by means of the upper; hence it says "at one time".