Thus one should know oneself to be of the nature of Existence-Consciousness-Bliss[Sat-Chit-Ananda].
Adi ShankaraYou never identify yourself with the shadows cast by your body, or with its reflection, or with the body you see in a dream or in your imagination. Therefore you should not identify yourself with this living body either.
Adi ShankaraThe witness of the three states of consciousness [waking, dream and deep sleep] and of the nature of Existence-Consciousness-Bliss is the Self
Adi Shankara