SB 11.17.32

One becomes glorious and enlightened by faithfully serving a bona fide spiritual master, who is expert in the Vedic way of life. Thus purified, one never engages in sinful activities, which immediately extinguish the fire of spiritual enlightenment; nor does one become foolish and small-minded, trying to exploit material nature for personal sense gratification. A purified human being is apṛthag-dhī, or without consciousness of duality, because he has been trained to observe the Supreme Personality of Godhead within all things. Such sublime consciousness should be systematically taught throughout the world so that human society will become peaceful and sublime.