Kauṣītaki (Śāṅkhāyana) Brāhmaṇa 3.3.25

3.3.25

sā vā asau yad ado amuṣyād ity asya upariṣṭād divi iva bhāti jyotir iva / (DpM)

it is that yonder which shines above this sun, as if in the sky, like a light.