觀無量壽佛經疏 1.11

1.11

四、辯說人差別者。凡諸經起說，不過五種：一者佛說，二者聖弟子說，三者天仙說，四者鬼神說，五者變化說。今此《觀經》是佛自說。問曰：「佛在何處說？為何人說？」答曰：「佛在王宮為韋提等說。」

Fourth, distinguishing the speakers: Whenever sūtras are spoken, there are no more than five kinds of speakers: first, spoken by the Buddha; second, spoken by holy disciples; third, spoken by devas and ṛṣis; fourth, spoken by spirits and ghosts; fifth, spoken by transformed beings. Now this Dhyāna Sūtra was spoken by the Buddha himself. Question: 'Where did the Buddha speak it? For whom did he speak it?' Answer: 'The Buddha spoke it in the royal palace for Vaidehī and others.'