Why did the gods of the Heaven of the Thirty Three come to hear this Dharma? Because their faith was inspired by hearing their prediction to buddhahood and a story of a past resolve.
1. The goddess Bodhisattvasamuccayā[1] asked why the gods from the Heaven of the Thirty Three came to hear the Dharma.
2. The Buddha replies:
a. They had heard the prophecy for awakening for Ruciraketu, who will become Suvarṇaratnākaracchatrakūṭa Buddha, until he will attain parinirvāṇa and his Dharma will disappear, then Rūpyaketu Buddha will arise, and when he attains parinirvāṇa, then Suvarṇaśataraśmiprabhāsaketu will arise.
b. Until those three Buddhas were prophesied by Śākyamuni Buddha, those gods of the Heaven of the Thirty Three did not follow the bodhisattva path, which involves giving up various pleasures that they enjoy and developing the six perfections.
c. At the time he prophesied their awakening, he declared that those gods would be born in the Sālendradhvajāgravatī world, and all be known as Prasannavadanotpalagandhakūṭa Buddha.
d. At that time, they also obtained exceeding reverence and faith towards this Sūtra particularly as a result of the power of a previous [story of a] resolve—which is recounted in the next chapter.
[1] “Assemblage/Collection of Bodhisattvas.”