The three fires
A central theme in the Vedas is the three fires – the Solar or heavenly (the Sun), the atmospheric (the wind) and the earthly fire (the fire of sacrifice, the cooking fire) – as expressed in the mantra, bhuh, bhuvah, svah. These three fires are homologised with various bodily powers, for example, Agni (the Earth-fire) is sometimes equated with speech, Vayu (the Wind-fire), with breath, and Aditya (the Solar-fire), with the eye.
Also, the Brahmanas provide many homologies between breaths and sacrifice. The Solar fire, in its various forms, gives life to the human body, and is the source of intelligence. The Sun is both the source and the place to which the vital soul returns following the death of the body.
The Satapatha Brahmana recounts how the creator, Prajapati, having “produced creatures” collapses & falls apart as the “vital air” (equated with vigour) leaves him. The vigour which leaves him becomes food. As Prajapati is the foundation of everything, the gods wish to restore him. The gods approach Agni – it is with the power of Agni (fire) that they wish to restore (rebuild?) Prajapati. Agni asks what his reward will be, and the gods reply that Prajapati is ‘food’ – and that with Agni as their mouth, they will eat that food. This establishes Agni as the ‘mouth’ of the gods, through which they receive the offerings of men. The SB clarifies the homology between wind, vigour, and the Sun:
“Now the vital air which went out from within him (i.e. Prajapati) is no other than the wind that blows yonder; and the vigour which went out of him is yonder sun; and the food which flowed from him is all the food which there is within the year.” 22.214.171.124
The gods heat Prajapati in the fire, and in doing so infuse him with the vital air, vigour, and food, restoring his body to completeness and enabling him to ‘stand upright’ – becoming ‘the worlds’:
“This (terrestrial) world truly is his foundation; and what fire there is in this world that is his (Pragâpati’s) downward vital air. And the air is his body, and what wind there is in the air, that is that vital air of his in the body. And the sky is his head; the sun and the moon are his eyes. The eye on which he lay is the moon: whence that one is much closed up, for the food flowed therefrom.” 126.96.36.199
There is also a relationship between the airs, the fires, and speech:
“That same Anushtubh, speech, is threefold. That fire, taking the form of the vital air, goes along with it (speech),- the fire which is on the Âhavanîya (altar) is the out-breathing, and yonder sun; and the fire which is on the Âgnîdhrîya is the through-breathing, and the wind which blows yonder; and the fire which is on the Gârhapatya is the in-breathing, and what fire there is here in this (earth-) world. And verily he who knows this makes up for himself the whole Vâk (speech), the whole vital air, the whole body (of Prajâpati).” 188.8.131.52