Brahma is stated here (in SB 3.15.5) to be born of the unmanifested. He is the incarnation of the mode of passion in material nature, which is the separated, external energy of the Supreme Lord

Expressions researched:
"Brahmā is stated here to be born of the unmanifested. He is the incarnation of the mode of passion in material nature, which is the separated, external energy of the Supreme Lord"

Srimad-Bhagavatam

SB Canto 3

The Vedas are the original scientific knowledge for all departments of understanding, and this knowledge of the Vedas was first impregnated into the heart of Brahmā by the Supreme Personality of Godhead. Therefore Brahmā is the original source of all scientific knowledge. He is born directly from the transcendental body of Garbhodakaśāyī Viṣṇu, who is never seen by any creature of this material universe and therefore always remains unmanifested. Brahmā is stated here to be born of the unmanifested. He is the incarnation of the mode of passion in material nature, which is the separated, external energy of the Supreme Lord.

SB 3.15.5, Translation and Purport

O original source of strength and scientific knowledge, all obeisances unto you! You have accepted the differentiated mode of passion from the Supreme Personality of Godhead. With the help of external energy you are born of the unmanifested source. All obeisances unto you!

The Vedas are the original scientific knowledge for all departments of understanding, and this knowledge of the Vedas was first impregnated into the heart of Brahmā by the Supreme Personality of Godhead. Therefore Brahmā is the original source of all scientific knowledge. He is born directly from the transcendental body of Garbhodakaśāyī Viṣṇu, who is never seen by any creature of this material universe and therefore always remains unmanifested. Brahmā is stated here to be born of the unmanifested. He is the incarnation of the mode of passion in material nature, which is the separated, external energy of the Supreme Lord.