In the Atharva Veda
Bhagavad-gita As It Is
BG Chapters 7 - 12
It was Kṛṣṇa who in the beginning instructed Brahmā in Vedic knowledge.
BG 10.8, Purport: In the Atharva Veda (Gopāla-tāpanī Upaniṣad 1.24) it is said, yo brahmāṇaṁ vidadhāti pūrvaṁ yo vai vedāṁś ca gāpayati sma kṛṣṇaḥ: "It was Kṛṣṇa who in the beginning instructed Brahmā in Vedic knowledge and who disseminated Vedic knowledge in the past."