अविनाशि तु तद्विद्धि येन सर्वमिदं ततम्। विनाशमव्ययस्यास्य न कश्चित् कर्तुमर्हति ॥

avināśhi tu tadviddhi yena sarvam idaṁ tatam vināśham avyayasyāsya na kaśhchit kartum arhati

Know That to be indestructible by whom all this is pervaded. Nor can any work the destruction of that imperishable One.

In plain words: Krishna says the soul fills everything and cannot be destroyed. No one can destroy what lasts forever.