Maitri (Maitrāyaṇīya) Upaniṣad 6.32

6.32

tasmādvā etasmādātmani sarve prāṇāḥ sarve lokāḥ sarve vedāḥ sarve devāḥ sarvāṇi ca bhūtānyuccaranti tasyopaniṣatsatyasya satyamiti atha yathārdraidhāgnerabhyāhitasya pṛthagdhūmā niścarantyevaṃ vā etasya mahato bhūtasya niḥśvasitametadyadṛgvedo yajurvedaḥ sāmavedo'tharvāṅgirasā itihāsaḥ purāṇam vidyā upaniṣadaḥ ślokāḥ sūtrāṇyanuvyākhyānāni vyākhyānānyasyaivaitāni viśvā bhūtāni ||

32. From Him, indeed, [who is] in the soul (ātman) come forth all breathing creatures, all worlds, all the Vedas, all gods, all beings. The mystic meaning (upaniṣad) thereof is : The Real of the real.

Now, as from a fire, laid with damp fuel, clouds of smoke separately issue forth; so, lo verily, from this great Being (bhūta) has been breathed forth that which is Rig-Veda, Yajur-Veda, Sāma-Veda, [Hymns of] the Atharvans and Aṅgirases, Legend (itihāsa), Ancient Lore (purāṇa), Sciences (vidyā), Mystic Doctrines (upaniṣad), Verses (śloka), Aphorisms (sūtra), Explanations (anuvyākhyāna), and Commentaries (vyākhyāna). From It, indeed, all beings here [were breathed forth].’