Chapter 8 · The Imperishable Absolute · Krishna said
Bhagavad Gita 8.20 — The eternal unmanifest
परस्तस्मात्तु भावोऽन्योऽव्यक्तोऽव्यक्तात्सनातनः। यः स सर्वेषु भूतेषु नश्यत्सु न विनश्यति ॥
parastasmāttu bhāvo'nyo'vyakto'vyaktātsanātanaḥ | yaḥ sa sarveṣu bhūteṣu naśyatsu na vinaśyati ||
Meaning
But beyond that unmanifest is another, eternal unmanifest reality, which does not perish even when all beings perish.