SB 3.6.23

buddhiṁ cāsya vinirbhinnāṁ
 vāg-īśo dhiṣṇyam āviśat
bodhenāṁśena boddhavyam
 pratipattir yato bhavet
Word for word: 
buddhim — intelligence; ca — also; asya — of the gigantic form; vinirbhinnām — being separately manifested; vāk-īśaḥ — Brahmā, lord of the Vedas; dhiṣṇyam — the controlling power; āviśat — entered in; bodhena aṁśena — with his part of intelligence; boddhavyam — the matter of understanding; pratipattiḥ — understood; yataḥ — by which; bhavet — so becomes.
Translation: 
When the intelligence of the gigantic form separately became manifest, Brahmā, the lord of the Vedas, entered into it with the partial power of understanding, and thus an object of understanding is experienced by the living entities.