Buddhist tradition holds that a person's debt to their parents cannot be repaid with material things, only by establishing them in the teaching, and the story of Maya after her death is the founder's own discharge of that debt. Reborn in the Trayastrimsa heaven, the heaven of the thirty-three gods on the summit of Mount Meru, she is out of reach of ordinary speech. In the seventh year after his awakening the Buddha ascends there and spends the three months of the rains retreat teaching her and the assembled gods the Abhidharma, the systematic analysis of mind and phenomena, sending a created double down to the human world to keep his daily alms round.
The descent is the part that became a festival. He returns to earth at Sankassa on a triple stairway of gold, silver and crystal, attended by Brahma and Shakra, at the full moon that ends the rains. Sankassa is one of the eight great pilgrimage places of Indian Buddhism, and the descent from the heaven is kept across Theravada countries at the end of the rains retreat, in Thailand and Laos and Myanmar, with processions and offerings.
The episode does a specific piece of doctrinal work as well as an emotional one. Placing the first teaching of the Abhidharma in a heaven, to an audience of gods, was one traditional answer to the observation that the Abhidharma texts are unlike the discourses in style and appear later in the record. Modern scholars read the Abhidharma as the product of several centuries of monastic analysis rather than a single delivered teaching, and note that the different schools produced different Abhidharma collections that do not agree. The story remains one of the most widely depicted scenes in Buddhist art, and its subject is a son teaching his mother.