'The altar (fire), O Gautama, is that world (heaven); the fuel is the sun itself, the smoke his rays, the light the day, the coals the quarters, the sparks the intermediate quarters. On that altar the Devas offer the sraddha libation (consisting of water). From that oblation rises Soma, the king (the moon).

In plain words: The king begins his teaching by describing the sky as a sacred fire, with the sun as its fuel and the day as its light. The gods offer faith into this fire, and from it the moon arises.