Bhagavad Gita, Chapter 3 verse 28: But he who knows the truth about the Gunas and their interactions, knowing it is the Gunas that act upon the Gunas, remains unattached.
The role of ego, the subtlest quality of intellect, is to ‘know the truth’ about who we really are. In discerning the truth about itself and the nature of its activity, the ego witnesses the Gunas emerge and this is how we ‘know the truth about the Gunas and their interactions’. [See 2.39 for the role of intellect and ego.]
The key to understanding functioning ego and how it bears witness to the Gunas is to appreciate how creation manifests from Veda. The Veda is the source of all intelligence and energy, and the unmanifest font of all activity. Out of Veda, Brahma the Creator. They are one: you can’t have a source of intelligence and energy without manifesting all of it, in fact, without perceiving it all, in a way, without proving it. Else, Veda is just an unknowable abstraction, either in part or in whole. It is the nature of Brahma to bring the source of creation into existence and manifest it in its pure glory of pure intelligence and energy to further evolution.
The ego knows unmanifest silence of the present before the three Gunas interact. Out of Brahma’s intelligence and energy arise the fundamental attributes of Nature, the three Gunas. Just below this ground zero of activity, the three Gunas of Nature arise as individual entities. Sattva, Rajas and Tomas are their own distinct energies of action. Nature comes into being and experience begins in the roles of experiencer, experienced and experiencing. At this level the ego is all three. Self-awareness begins. Operating at this finest level of Creation, just before action occurs, the ego ‘knows the truth’ about the Gunas individuality as well as all manner in which they interact to further Nature’s evolution.
The ego has a ringside seat to the Gunas emergence and interactions, and most importantly, the source and nature of its own functioning. Those who experience separation from activity (previous verse) sit in this ringside seat. They experience the genesis of their own functioning mind which is silence. This is the ‘he who know the truth about Gunas and their interactions, knowing it is the Gunas that act upon the Gunas.’ He ‘remains unattached’ and separate from activity and in silence, when serving the desires of others, either by electing to do so or more so by serving Nature’s desires in Cosmic and God consciousness (previous verse).
The ego knows everything and that is why we feel at home with everything.