Upanishads say,
Sat-Chit-Ananda - Sat (Existence, Reality, or Being), Chit
(Consciousness, or Knowledge), and Ananda (Bliss).
Existence, Consciousness and Bliss are not attributes of ‘Brahman’
but ‘Brahman’ Itself.
"Brahman is Sat-Chit-Ananda (ever-present,
ever-conscious, ever-blissful)."
SAT (Existence)
"In the beginning, this [universe] was Being (Sat)
alone, one only without a second."
-
Chandogya Upanishad 6.2.1 also Aitareya
Upanishad 1.1.1
"All this that we see in the world is Brahman."
Sanskrit: sarvam khalv idam brahma.
-
Chandogya Upanishad 3.14.1
"Brahman is Reality, Knowledge, and Infinity."
-
Taittiriya Upanishad 2.1.3
CHIT
(Consciousness)
"Brahman is Consciousness." Sanskrit: prajnanam
brahma.
-
Aitareya Upanishad 3.1.3
ANANADA (Bliss)
"Brahman is bliss (ananda)."
-
Taittiriya Upanishad 3.6.1