The Mukhya Upaniṣads

Maitrī · Prapāṭhaka 6 · Maitrī 6.1

Passage 37

तस्मादोमित्यनेनैतदुपासीतापरिमितं तेजस्तत्त्रेधभिहितमग्नावादित्ये प्राणेऽथैषा नाड्यन्नबहुमित्येषाग्नौ हुतमादित्यं गमयति अतो यो रसोऽस्रवत् स उद्गीथं वर्षति तेनेमे प्राणाः प्राणेभ्यः प्रजा इत्यत्रोदाहरन्ति -- यद्धविरग्नौ हूयते तदादित्यं गमयति तत्सूर्यो रश्मिभिर्वर्षति तेनान्नं भवति अन्नाद्भूतानामुत्पत्तिरित्येवं ह्याह ।अग्नौ प्रास्ताहुतिः सम्यगादित्यमुपतिष्ठते ।आदित्याज्जायते वृष्टिर्वृष्टेरन्नं ततः प्रजाः ॥ ॥६.३७ ॥

In plain words

Therefore let a man worship with Om this unmeasured splendour, which is declared in three places: in fire, in the sun and in the breath. Now this channel bears much food; and what is offered here in the fire it sends to the sun; and the savour that flows from it rains down as the Udgītha. From that come these breaths, and from the breaths creatures. On this they quote: "Whatever oblation is offered in the fire, that it sends to the sun; the sun rains it down with his rays; from that comes food, and from food the arising of beings." So it is said: "The oblation cast into the fire duly waits upon the sun; from the sun is born rain, from rain food, and from that creatures."