Chandogya Upanishad 4.11

atha hainaṃ gārhapatyo 'nuśaśāsa pṛthivy agnir annam āditya iti ya eṣa āditye puruṣo dṛśyate so 'ham asmi sa eva aham asmi iti

After that the Gârhapatya fire taught him: 'Earth, fire, food, and the sun (these are my forms, or forms of Brahman). The person that is seen in the sun, I am he, I am he indeed.

sa ya etam evaṃ vidvān upāste apahate pāpakṛtyām lokī bhavati sarvam āyur eti jyog jīvati na asya avarapuruṣāḥ kṣīyante upa vayaṃ taṃ bhuñjāmo 'smiṃś ca loke 'muṣmiṃś ca ya etam evaṃ vidvān upāste

'He who knowing this meditates on him, destroys sin, obtains the world (of Agni Gârhapatya), reaches his full age, and lives long; his descendants do not perish. We guard him in this world and in the other; whosoever knowing this meditates on him.'