Bṛhadāraṇyaka Upaniṣad ("Great Forest Teaching") 2.5.4

2.5.4

ayaṃ vāyuḥ sarveṣāṃ bhūtānāṃ madhvasya vāyoḥ sarvāṇi bhūtāni madhu yaścāyamasminvāyau tejomayo'mṛtamayaḥpuruṣo yaścāyamadhyātmaṃ prāṇastejomayo'mṛtamayaḥ puruṣo'yameva sa yo'yamātmedamamṛtamidaṃ brahmedam̐ sarvam

This air is the honey of all beings, and all beings are the honey of this air. Likewise this bright, immortal person in this air, and that bright, immortal person existing as breath in the body (both are madhu). He indeed is the same as that Self, that Immortal, that Brahman, that All.