Bhagavad Gita 2.24

It is impenetrable; it cannot be drowned, scorched, or dried. It is eternal, all-pervasive, unchanging, immovable, and most ancient.

अच्छेद्योऽयमदाह्योऽयमक्लेद्योऽशोष्य एव च।
नित्यः सर्वगतः स्थाणुरचलोऽयं सनातनः॥

acchedyo'yamadāhyo'yamakledyo'śoṣya eva ca|
nityaḥ sarvagataḥ sthāṇuracalo'yaṃ sanātanaḥ||

English translation (above): Shri Purohit Swami (1935), public domain. Sanskrit text via github.com/gita/gita (Unlicense).