Saṅkhapāla Jātaka (No.524)
The Bodhisatta was born as Duyyodhana, son of the king of Rājagaha. When he came of age his father handed over the kingdom to him, became an ascetic, and lived in the royal park. There Duyyodhana frequently visited him; finding this inconvenient, the ascetic went to Mahiṃsaka-raṭṭha and lived in a hut on a bend of the Kaṇṇaveṇṇā river, which flows from the Saṅkhapāla Lake near Mount Candaka. There he was visited by the Nāga king Saṅkhapāla, to whom he taught the Dhamma. Later, Duyyodhana discovered the whereabouts of the ascetic and visited him. There he saw the Nāga-king, and, impressed by his great magnificence, desired to visit the Nāga-world. On his return to the capital, Duyyodhana engaged in works of merit, and was born after death in the Nāga world and became its king under the name of Saṅkhapāla. In the course of time, he grew weary of his magnificence, and, leaving the Nāga world, lived near the Kaṇṇaveṇṇā, on an ant-hill, keeping the holy fast. As he lay there, sixteen men, roaming in the forest, saw him and seized him. They drove stakes into his body, and made holes in the stakes and fastened ropes to them in order to drag him along. However, Saṅkhapāla showed no resentment. A landowner of Mithilā, called Āḷāra, saw him being ill-treated and had him released. Thereupon, Saṅkhapāla invited Āḷāra to the Nāga world, and Āḷāra lived there for one year. He later became an ascetic, and, in due course, visited Bārāṇasī, where he told the king the story of his visit to the Nāga world. After the rains he returned to the Himavā.
The story was told to some laymen who kept the fast.
The Bodhisatta’s father is identified with Mahā-Kassapa, the king of Bārāṇasī with Ānanda, and Āḷāra with Sāriputta. J.v.161‑71. See also Āḷāra.
The story is given in the Cariyāpiṭaka (ii.10; see also J.i.45; MA.ii.617; BuA.50) to illustrate the perfection of morality (sīla-pāramī).