Verse 2.1.8

सप्त प्राणाः प्रभवन्ति तस्मात्सप्तार्चिषः समिधस्सप्तहोमाः ।
सप्त इमे लोका येषु चरन्ति प्राणा गुहाशया निहिताः सप्त सप्त ॥ ८ ॥

sapta prāṇāḥ prabhavanti tasmātsaptārciṣaḥ samidhassaptahomāḥ |
sapta ime lokā yeṣu caranti prāṇā guhāśayā nihitāḥ sapta sapta || 8 ||

8. From him mare borne the seven pranas, the seven flames, their sevenfold fuel, the sevenfold oblation and these seven lokas where the pranas move, seven and seven in each living being lying in the cave, there fixed.

Shankara’s Commentary:

Com.—Again the seven pranas, i.e., (organs of sense) in the head are born of this purusha alone. ‘Their seven flames,’ their light which enlightens their objects. Similarly, the sevenfold fuel, their sevenfold objects; for, it is by these objects that the pranas, i.e., organs of sense are fed. ‘The sevenfold oblations’, the perceptions of the sevenfold objects; for, another Sruti says: “He offers the oblation which consists in the perception of the objects by the senses.” The seven lokas, i.e., the seats of the senses where the pranas move. The clause “where the pranas move” is intended to exclude the vital airs, i.e., prana, apana and the rest. ‘Lying in the cave,’ lying during sleep in the body or the heart. ‘Fixed,’ fixed by the creator. ‘Seven and seven’, in every living thing. The meaning of the context is that all karma performed by knowing men who propitiate their Atman and the fruits of such karma as well as the karma performed by the ignorant and their means and fruits; all these proceed only from the highest and the omniscient purusha.