Muṇḍaka Upaniṣad 1.1.2

1.1.2

atharvaṇe yāṃ pravadeta brahmā atharvā tāṃ purovācāṅgire brahmavidyām.
sa bhāradvājāya satyavahāya prāha bhāradvājo 'ṅgirase parāvarām.

2. What Brahmā taught to Atharvan,
Even that knowledge of Brahma, Atharvan told in ancient time to Aṅgir.
He told it to Bhāradvāja Satyavāha;
Bhāradvāja, to Aṅgiras—both the higher and the lower [knowledge].