Chandogya Upanishad
Prapathaka III, Khanda 6
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.
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.