觀無量壽佛經疏 4.10

4.10

Fourth, from "What are the three?" down to "they will certainly be born in that land", it directly clarifies and determines the three minds as the correct cause. There are two points: first, clarifying that because the World-Honoured One reveals the benefits in accordance with beings' capacities, his inner intention is profound and difficult to know, such that without the Buddha himself asking and investigating, there would be no way to understand it; second, clarifying that the Tathāgata in turn answers himself the number of the aforementioned three minds.