Maitri (Maitrāyaṇīya) Upaniṣad 6.8

6.8

eṣa hi khalvātmeśānaḥ śambhurbhavo rudraḥ prajāpatirviśvasṛk hiraṇyagarbhaḥ satyaṃ prāṇo haṃsaḥ śāstā viṣṇurnārāyaṇo'rkaḥ savitā dhātā vidhātā samrāḍindra induriti ya eṣa tapatyagnirivāgninā pihitaḥ sahasrākṣeṇa hiraṇmayenāṇḍena eṣa vā jijñāsitavyo'nveṣṭavyaḥ sarvabhūtebhyo'bhayaṃ datvāraṇyaṃ gatvātha bahiḥkṛtvīndriyārthānsvāccharīrādupalabheta enamiti |
viśvarūpaṃ hariṇaṃ jātavedasaṃ parāyaṇaṃ jyotirekaṃ tapantam |
sahasraraśmiḥ śatadhā vartamānaḥ prāṇaḥ prajānāmudayatyeṣa sūryaḥ ||

8. This Soul (Ātman), assuredly, indeed, is Īśāna (Lord), Śambhu (the Beneficent), Bhava (the Existent), Rudra (the Terrible), Prajāpati (Lord of Creation), Viśvasṛij (Creator of All), Hiraṇyagarbha (Golden Germ), Truth (satya), Life (prāṇa), Spirit (haṁsa), Śāstṛi (Punisher, or Commander, or Teacher), Vishṇu (Pervader), Nārāyaṇa (Son of Man), Arka (the Shining), Savitṛi (Vivifier, the sun), Dhātṛi (Creator), Vidhātṛi (Ordainer), Samrāj (Sovereign), Indra, Indu (the moon). He it is who gives forth heat, who is covered with a thousand-eyed, golden ball, like a fire [covered] with a fire. Him, assuredly, one should desire to know. He should be searched for.

Having bidden peace to all creatures, and having gone to the forest, then having put aside objects of sense, from out of one’s own body one should perceive Him,

Who has all forms, the golden one, all-knowing,
The final goal, the only light, heat-giving.
The thousand-rayed, the hundredfold revolving,
Yon sun arises as the life of creatures.