Khandogya-Upanishad: Third Prapathaka, Sixth Khanda
1. On the first of these nectars (the red light, which represents fame, glory of countenance, vigour, strength, health) the Vasus live, with Agni at their head. True, the Devas do not eat or drink, but they enjoy by seeing the nectar.
2. They enter into that (red) colour, and they rise from that colour.
3. He who thus knows this nectar, becomes one of the Vasus, with Agni at their head, he sees the nectar and rejoices. And he, too, having entered that colour, rises again from that colour.
4. So long as the sun rises in the east and sets in the west, so long does he follow the sovereign supremacy of the Vasus.