Then Ushasta, the son of Chakra, questioned him. "Yajnavalkya," said he, "explain to me the Brahman that is immediately and directly perceived, the self that is within all." (Yajnavalkya replied) "This is your self that is within all." (Ushasta asked) "Which self is within all, Yajnavalkya?" (Yajnavalkya replied) "That which breathes through the prana is yourself that is within all. That which moves downward through the apana is your self that is within all. That which pervades through the vyana is your self that is within all. That which goes out with the udana is your self that is within all. This is your self that is within all."
Ushasta, the son of Chakra, said - "You have explained it as one might say - 'Such is a cow,' 'Such is a horse.' Tell me precisely the Brahman that is immediate and direct, the self that is within all." (Yajnavalkya replied) "This is your self that is within all." (Ushasta asked) "Which is within all, Yajnavalkya?" (Yajnavalkya replied) "You cannot see the seer of seeing; you cannot hear the hearer of hearing; you cannot think of the thinker of thinking; you cannot know the knower of knowing. This is your self that is within all; everything else but this is perishable." Thereupon Ushasta, the son of Chakra, held his peace.