Summary of chapter 6 of the Agni Mahā Purana is as follows:
Bhagavān took birth as Vāmana, the dwarf brahmin, to restore the three worlds that the demon king Bali had wrested from the gods through his immense tapas and generosity. Approaching Bali's great sacrifice, Vāmana begged for three paces of ground. Despite his guru Śukrācārya's warning, Bali — true to his reputation for limitless generosity — granted the boon. Vāmana then expanded to cosmic proportions: with one step he covered the earth, with the second he covered the heavens, and for the third he placed his foot on Bali's own head, sending him to Pātāla. Bhagavān's compassion for Bali is revealed when he grants the demon sovereignty over Pātāla and promises to stand as his doorkeeper. The episode establishes the principle that even a king's highest virtue must yield to Bhagavān's sovereignty.