Maitri (Maitrāyaṇīya) Upaniṣad 7.5

7.5

mitrāvaruṇau paṅktistriṇavatrayastriṃśo śākvararaivate hemanta śiśirā udāno'ṅgirasaścandramā ūrdhvā udyanti tapanti varṣanti stuvanti punarviśanti antarvivareṇekṣanti praṇavākhyaṃ praṇetāram bhārūpam vigatanidram vijaram vimṛtyum viśokam ||

5. Mitra and Varuṇa, the Paṅkti meter, the Triṇava and Trayastriṁśa hymns, the Śākvara and Raivata chants, the winter and the dewy seasons, the Udāna breath, the Aṅgirases, the moon, issue forth above. They shine, they rain, they praise, they enter again within and peer through an opening.

. . . Him who is called *Om*, a leader, brilliant, sleepless, ageless, deathless, sorrowless.