Maitrayaniya Upanishad 6.37

37. Therefore, one should reverence with *Om* that unlimited bright power. This has been manifested in threefold wise: in fire, in the sun, and in the breath of life.

Now, the channel [which is between them] causes the abundance of food that has been offered in this fire to go unto the sun. The moisture which flows therefrom rains down like a chant (Udgītha). Thereby living creatures here exist. From living creatures come offspring.

On this point they quote: ‘The oblation which has been offered in the fire it causes to go unto the sun. The sun rains that down with its rays. Thereby arises food; from food, the production of beings.’

For thus has it been said:—

The offering fitly cast in fire
Arises up unto the sun.
From out the sun, rain is produced;
From rain, food; living creatures thence.

38. He who performs the Agnihotra sacrifice rends the net of eager desire (*lobha*).

Thence, having cut off confusion (*sammoha*), he no longer approves of anger.

Meditating upon desire, he then cuts through the fourfold sheath of Brahma.

Thence he goes to the highest ether. There, truly, having cut through the spheres of the sun, of the moon, of fire, and of Pure Being, himself being purified (śuddha), he sees the Intelligence (caitanya) which abides within Pure Being (sattva), immovable, immortal, unshaken, enduring, named Vishṇu, the ultimate abode, endowed with true desires and with omniscience, independent, which stands in its own greatness. On this point they quote:—

In the midst of the sun stands the moon (Soma);
In the midst of the moon, fire.
In the midst of fire stands Pure Being (sattva).
In the midst of Pure Being stands the Unshaken One.