Mahabharata, Book 5, Section XVIIउद्योगपर्व

“Salya said, ‘Now when the great Indra, the intelligent chief of the gods, was deliberating with the guardians of the world and other deities upon the means of slaying Nahusha, there appeared at that spot the venerable ascetic Agastya. And Agastya honoured the lord of the gods and said, “How fortunate that thou art flourishing after the destruction of that being of universal form, as also that of Vritra. And how fortunate, O Purandara, Nahusha hath been hurled from the throne of heaven. How fortunate, O slayer of Vala, that I behold thee with all thy enemies killed."

“‘Indra said, “Hath thy journey hither been pleasant, O great saint, I am delighted to see thee. Accept from me water for washing thy feet and face, as also the Arghya and the cow.”’

“Salya continued, ‘Indra, well-pleased, began to question that best of saints and greatest of Brahmanas when he was seated on a seat after receiving due honours, thus, O revered saint, O best of Brahmanas, I wish to have it recited by thee how Nahusha of vicious soul was hurled from heaven.

“‘Agastya said, “Listen, O Indra, to the pleasant narrative how the wicked and vicious Nahusha, intoxicated with pride of strength, had been hurled from heaven. The pure-spirited Brahmanas and celestial saints, while carrying him, weary with toil, questioned that vicious one, O best of victors, saying, ‘O Indra, there are certain hymns in the Vedas, directed to be recited while sprinkling the cows. Are they authentic or not?’ Nahusha, who had lost his senses by the operation of the Tamas, told them that they were not authentic. The saints then said, ‘Thou art tending towards unrighteousness; thou takest not to the righteous path. The greatest saints have formerly said they are authentic, O Indra.’ And incited by Untruth, he touched me on my head with his foot. At this, O lord of Sachi, he became divested of power and of good looks. Then, as he was agitated and overpowered with fear, I spoke to him, ‘Since thou hast pronounced as spurious the unexceptionable hymns of the Veda which have been recited by Brahmarsis (Brahmana saints), and since thou hast touched my head with thy foot, and since thou, O ignorant wretch, hast turned these unapproachable saints, equal to Brahma, into animals for carrying thee, therefore, O wretch, be divested of thy lustre, and being hurled headlong, fall thou from heaven, the effect of all thy good deeds being exhausted. For ten thousand years, thou shalt, in the form of an enormous snake, roam over the earth. When that period is full, thou mayst come back to heaven. Thus hath that wretch been hurled from the throne of heaven, O repressor of foes.’ How fortunate, O Indra, that we are flourishing now. That thorn of the Brahmanas hath been killed. O lord of Sachi, repair thou to heaven, protect the worlds, subdue thy senses, subdue thy foes, and be glorified by the great saints.”’

“Salya continued, ‘Then, O ruler of men, the gods, and the bands of great saints were exceedingly pleased. And so also were the Pitris, the Yakshas, the Snakes, the Rakshasas, the Gandharvas, and all the bands of celestial nymphs. And the tanks, the rivers, the mountains, and the seas also were highly pleased. And all came up and said, “How fortunate, O slayer of foes, that thou art flourishing! How fortunate, that the intelligent Agastya hath killed the vicious Nahusha! How fortunate that the vile individual hath been turned into a snake to roam over the earth!”’"