The Prose Edda 1.5

Gangleri asked: "How were things wrought, ere the races were and the tribes of men increased?" Then said Hárr: "The streams called Ice-waves, those which were so long come from the fountain-heads that the yeasty venom upon them had hardened like the slag that runs out of the fire,—these then became ice; and when the ice halted and ceased to run, then it froze over above. But the drizzling rain that rose from the venom congealed to rime, and the rime increased, frost over frost, each over the other, even into Ginnungagap, the Yawning Void." Then spake Jafnhárr: "Ginnungagap, which faced toward the northern quarter, became filled with heaviness, and masses of ice and rime, and from within, drizzling rain and gusts; but the southern part of the Yawning Void was lighted by those sparks and glowing masses which flew out of Múspellheim." And Thridi said: "Just as cold arose out of Niflheim, and all terrible things, so also all that looked toward Múspellheim became hot and glowing; but Ginnungagap was as mild as windless air, and when the breath of heat met the rime, so that it melted and dripped, life was quickened from the yeast-drops, by the power of that which sent the heat, and became a man's form. And that man is named Ymir, but the Rime-Giants call him Aurgelimir; and thence are come the races of the Rime-Giants, as it says in Völuspá the Less:

All the witches spring from Witolf, All the warlocks are of Willharm, And the spell-singers spring from Swarthead; All the ogres of Ymir come.

But concerning this says Vafthrúdnir the giant:

Out of the Ice-waves issued venom-drops, Waxing until a giant was; Thence are our kindred come all together,— So it is they are savage forever."

Then said Gangleri: "How did the races grow thence, or after what fashion was it brought to pass that more men came into being? Or do ye hold him God, of whom ye but now spake?" And Jafnhárr answered: "By no means do we acknowledge him God; he was evil and all his kindred: we call them Rime-Giants. Now it is said that when he slept, a sweat came upon him, and there grew under his left hand a man and a woman, and one of his feet begat a son with the other; and thus the races are come; these are the Rime-Giants. The old Rime-Giant, him we call Ymir."