Brihadaranyaka-Upanishad: Third Adhyâya, Third Brahmana
1. Then Bhugyu Lahyayani asked. “Yagnavalkya,” he said, “we wandered about as students, and came to the house of Patanikala Kapya. He had a daughter who was possessed by a Gandharva. We asked him, ‘Who art thou?’ and he (the Gandharva) replied: ‘I am Sudhanvan, the Angirasa.’ And when we asked him about the ends of the world, we said to him, ‘Where were the Parikshitas?’ Where then were the Parikshitas, I ask thee, Yagnavalkya, where were the Parikshitas?”
2. Yagnavalkya said: “He said to thee, I suppose, that they went where those go who have performed a horse-sacrifice.”
He said: “And where do they go who have performed a horse-sacrifice?”
Yagnavalkya replied: “Thirty-two journeys of the car of the sun is this world. The earth surrounds it on every side, twice as large, and the ocean surrounds this earth on every side, twice as large. Now there is between them a space as large as the edge of a razor or the wing of a mosquito. Indra, having become a bird, handed them (through the space) to Vayu (the air), and vayu (the air), holding them within himself, conveyed them to where they dwell who have performed a horse-sacrifice. Somewhat in this way did he praise vayu indeed. Therefore vayu (air) is everything by itself, and Vayu is all things together. He who knows this, conquers death.” After that Bhugyu Lahyayani held his peace.