The Vishnu Purana
Chapters
The Vishnu Purana: Book V: Chapter I

The unborn, universal Hari, having heard with his mental ear these eulogiums, was pleased, and thus spake to Brahmá: "Tell me, Brahmá, what you and the gods desire: speak boldly, certain of success." Brahmá, beholding the divine, universal form of Hari, quickly prostrated himself, and again renewed his praises. "Glory to thee, the thousand-formed, the thousand-armed, the many-visaged, many-footed; to thee, the illimitable author of creation, preservation, and destruction; most subtile of the subtile, most vast of the great: to thee, who art nature, intellect, and consciousness; and who art other spirit even than the spiritual root of those principles 22. Do thou shew favour upon us. Behold, lord, this earth, oppressed by mighty Asuras, and shaken to her mountain basements, comes to thee, who art her invincible defender, to be relieved from her burden. Behold me, Indra, the Aswins, Varuńa, and Yama, the Rudras, the Vasus, the suns, the winds, fire, and all other celestials, prepared to execute whatever thou shalt will that we shall do. Do thou, in whom there is no imperfection, O sovereign of the deities, give thy orders to thy servants: lo, we are ready."

When Brahmá had ended, the supreme lord plucked off two hairs, one white and one black, and said to the gods, "These my hairs shall descend upon earth, and shall relieve her of the burden of her distress 23.

[paragraph continues] Let all the gods also, in their own portions, go down to earth, and wage war with the haughty Asuras, who are there incorporate, and who shall every one of them be destroyed. Doubt not of this: they shall perish before the withering glance of mine eyes. This my (black) hair shall be impersonated in the eighth conception of the wife of Vasudeva, Devakí, who is like a goddess; and shall slay Kansa, who is the demon Kálanemi." Thus having spoken, Hari disappeared; and the gods bowing to him, though invisible, returned to the summit of mount Meru, from whence they descended upon earth.