The Vedanta-Sutras with the Commentary by Sankaracarya
“ For as long as the individual soul does not free itself from Nescience in the form of duality—which Nescience may be compared to the mistake of him who in the twilight mistakes a post for a man—and does not rise to the knowledge of the Self, whose nature is unchangeable, eternal Cognition—which expresses itself in the form 'I am Brahman'—so long it remains the individual soul. ”
