Bhagavad Gita 18.21
The knowledge that perceives the manifold existence in all beings as separate comes from passion.
पृथक्त्वेन तु यज्ज्ञानं नानाभावान्पृथग्विधान्।वेत्ति सर्वेषु भूतेषु तज्ज्ञानं विद्धि राजसम्॥pṛthaktvena tu yajjñānaṃ nānābhāvānpṛthagvidhān|vetti sarveṣu bhūteṣu tajjñānaṃ viddhi rājasam||
English translation (above): Shri Purohit Swami (1935), public domain. Sanskrit text via github.com/gita/gita (Unlicense).