CC Madhya 20.303
vyaṣṭi sṛṣṭi kare kṛṣṇa brahmā-rūpa dhari’
“Such a devotee is empowered by Garbhodakaśāyī Viṣṇu. In this way, an incarnation of Kṛṣṇa in the form of Brahmā engineers the total creation of the universe.
The Garbhodakaśāyī Viṣṇu puruṣa-avatāra expansion of Lord Viṣṇu accepts the material modes — sattva-guṇa, rajo-guṇa and tamo-guṇa — and thus incarnates as Lord Viṣṇu, Brahmā and Śiva. These are incarnations of the material qualities. Among the many superior living entities qualified with pious activities and devotional service, one, called Lord Brahmā, is infused with the quality of passion by the supreme will of Garbhodakaśāyī Viṣṇu. Thus Lord Brahmā becomes the incarnation of the creative energy of the Lord.