As pure water poured into pure water becomes the very same, so does the Self of the illumined man or woman verily become one with the Godhead.
Katha Upanishad
Know the Self as Lord of the chariot, the body as the chariot itself, the discriminating intellect as the charioteer, and the mind as the reins. The senses, say the wise, are the horses; selfish desires are the roads they travel.
Katha Upanishad
Know one, know all.
Katha Upanishad
The self-existent Lord pierced the senses to turn outward. Thus we look to the world outside and see not the Self within us. A sage withdrew his senses from the world of change and, seeking immortality, looked within and beheld the deathless self.
Katha Upanishad