What, then, is that which is ever real? Listen :—
अविनाशि तु तद्विद्धि येन सर्वमिदं ततम् ।
विनाशमव्ययस्यास्य न कश्चित्कर्तुमर्हति ॥ १७ ॥
avināśi tu tadviddhi yena sarvamidaṃ tatam .
vināśamavyayasyāsya na kaścitkartumarhati .. 17 ..
Read the commentary
Unlike the unreal, That—you must understand—does not vanish; That, the Brahman, the ‘Sat’, the Real, by which all this world, including the akasa, is pervaded, just as pots and other objects are pervaded by the akasa or space. Brahman does not undergo increase or diminution and is therefore inexhaustable. This Brahman, the ‘Sat’, is not exhausted in Itself; for, unlike the body It has no parts. Nor does It diminish by (loss of) anything belonging to It; for, nothing belongs to the Self. Devadatta, for instance, is ruined by loss of wealth; but Brahman does not suffer loss in that way. Wherefore, nobody can bring about the disappearance or destruction of the inexhaustible Brahman. Nobody—not even the Īśvara, the Supreme Lord—can destroy the Self. For, the Self is Brahman Itself and one cannot act upon oneself.
What, then, is the unreal (asat), whose existence is not constant? Listen :