योगवासिष्ठः yogavāsiṣṭhaḥ - book-3, chapter-11, verse-10

कज्जलान्न यथा कार्ष्ण्यं शैत्यं च न यथा हिमात् ।
पृथगेवं भवेद्बुद्धं जगन्नास्ति परे पदे ॥ १० ॥

kajjalānna yathā kārṣṇyaṃ śaityaṃ ca na yathā himāt ,
pṛthagevaṃ bhavedbuddhaṃ jagannāsti pare pade 10

10. As the collyrium is no other than blackness, and as there is no difference between frost and its coldness, so the world is not otherwise than the great Brahma himself.