Bhagavad Gita · 8.9

कविं पुराणमनुशासितार-मणोरणीयांसमनुस्मरेद्यः।सर्वस्य धातारमचिन्त्यरूप-मादित्यवर्णं तमसः परस्तात्॥

kaviṁ purāṇam anuśhāsitāram aṇor aṇīyāṁsam anusmared yaḥ sarvasya dhātāram achintya-rūpam āditya-varṇaṁ tamasaḥ parastāt

One who meditates on the Supreme as the omniscient, the most ancient, the controller of all, subtler than the subtlest, the sustainer of all, whose form is inconceivable, who is luminous like the sun, and who is beyond all darkness —

— Bhagavad Gita 8.9

Source: Sacred-Texts.com (Sanskrit) + Bhagavad-Gita.io (translations)