Verse 2.17
Self is all-pervading (atma sarva gatha:) the non-self is limited by space.
अविनाशि तु तद्विद्धि येन सर्वमिदं ततम् |
विनाशमव्ययस्यास्य न कश्चित्कर्तुमर्हति || 17||
avināśhi tu tad viddhi yena sarvam idaṁ tatam
vināśham avyayasyāsya na kaśhchit kartum arhati
avināśhi—indestructible; tu—indeed; tat—that; viddhi—know; yena—by whom; sarvam—entire,everything; idam—this; tatam—pervaded; vināśham—destruction; avyayasya—of the unchangeable; asya—of it; na kaśhchit—no one; kartum—to cause; arhati—is able
That which pervades everything here, know it to be indestructible. No one has the ability to cause destruction to the imperishable.
Self is all pervading (atma sarva gatha:) the non self is limited by space.
The relation between sat and asat.
The word tat in this verse indicates the self, which was understood as the reality by the jnanis, has no abhava: (non-existence). The self pervades anything and everything in this universe, hence it is avinashi, indestructible. But this universe is prone to transformation and destruction and therefore it is asat or mitya. Sat is not dependent on asat but asat or mitya is dependent on sat for its existence. A pot is dependent on clay for its existence. We cannot have a pot existing independently of clay, assuming all pots are made of clay. If we remove clay from the pot, there will be no pot.
Self is unchangeable (atma avyaya:)
The word avyaya means that which has no deterioration. Krishna says no one has the ability to cause destruction, vinasham to this atma. He presents a reason for this statement as well. He states that everything in this universe and the universe itself is pervaded by atma and hence atma does not have a secondary identity apart from it to cause its destruction. Chandogya Upanishad says yekamevat advidteeyam, the self is only one. Though it pervades all beings, actions, objects and situations, it still remains a non dual entity.
Shankara in his commentary states that even the almighty Ishwara cannot destroy the sat-chit-ananda atma, since Ishwara himself is atma.
Atma = Brahman; Ishwara = Brahman; hence atma = Ishwara. Everything is created by Ishwara, everything except atma. There is no creator-creation relationship (kartru-karana sambandha) between atma and Ishwara. But for a devotee, the lord-devotee relationship exists because the devotee, though he himself is atma, worships Ishwara with his mind, body and senses and receives the fruits of his devotion from the lord himself. Even here atma does not receive anything. Only the body, mind and senses are the receptors of either lord’s punishment or blessings.
Is it possible for atma to destroy itself like one kills himself by committing suicide? No. Because atma has no limbs, niravayavatvam. By stating it is a single identity that pervades everything it is mentioned it has no limbs to destroy itself.
Clouds of various sizes crowd the sky or space, but they never add anything to or subtract anything from the space by their appearance. Likewise, atma is called chidakasam, meaning a space which is consciousness. In the space of consciousness, the whole universe appears and vanishes. But this appearance or disappearance never adds anything to or subtract anything from atma.