avināśi tu tadviddhi yena sarvamidaṃ tatam |vināśamavyayasyāsya na kaścit kartumarhati ||
But know that to be indestructible by which all this is pervaded. No one is able to bring about the destruction of this imperishable one.
Explanation
Krishna is instructing the grieving Arjuna, explaining what is real and lasting as opposed to what passes away. He points to the imperishable (avināśi) reality that pervades the whole world and cannot be destroyed by anyone. Most traditions take this as the self (ātman), though Advaita reads it as the one Brahman present in all, while theistic schools see the individual self as distinct from, yet dependent on, the Supreme.