As previous studies have reported, Indra (Skt: Śakra; Pāli: Sakka), or lord of the gods in the Trāyastriṃśa heaven, visited the Buddha and listened to his teachings in the Sakkapañha-suttanta of the Dīgha-Nikāya (DN) No. 21, and its corresponding Chinese translations from Sanskrit Āgama sūtras.
Indra’s motivation for visiting the Buddha mentioned in DN is not concrete, because it is only stated that he had a zeal for meeting the Buddha. Thus, it is difficult to comprehend why he had this zeal. However, its commentary (aṭṭhakathā), the Sumaṅgalavilāsinī, adds an explanation that he asked for relief from death because the five signs of decay occurred on his body.
That is to say, Indra’s motivation for visiting the Buddha is not explicitly explained in DN and its corresponding Chinese translations from Sanskrit Āgamas, but in the commentary on DN.
In this paper, I point out that Indra’s motivation is also described clearly in the story of Indra’s death in the Chinese translations of the Abhidharma Mahāvibhāṣa and elsewhere. Some of these references were compiled earlier than the Pāli commentaries.