Bhagavad Gita 13.3

I am the omniscient Self that abides in the realm of matter; knowledge of matter and of the all-knowing Self is wisdom.

क्षेत्रज्ञं चापि मां विद्धि सर्वक्षेत्रेषु भारत।
क्षेत्रक्षेत्रज्ञयोर्ज्ञानं यत्तज्ज्ञानं मतं मम॥

kṣetrajñaṃ cāpi māṃ viddhi sarvakṣetreṣu bhārata|
kṣetrakṣetrajñayorjñānaṃ yattajjñānaṃ mataṃ mama||

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