CHĀNDOGYA UPANISHAD · 4.11.1

अथ हैनं गार्हपत्यो ऽनुशशास पृथिव्य् अग्निर् अन्नम् आदित्य इति ।
य एष आदित्ये पुरुषो दृश्यते सो ऽहम् अस्मि स एव अहम् अस्मि इति ॥

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.

F. Max Müller · The Upanishads, Sacred Books of the East 1 (1879)