The Mukhya Upaniṣads

Kauṣītaki · Adhyāya 4 · Kauṣītaki 4.1

Passage 9

स होवाच बालाकिर्य एवैषोऽप्सु पुरुषस्तमेवाहमुपास इति तं होवाचाजातशत्रुर्मा मैतस्मिन्समवादयिष्ठा नाम्न्यस्यात्मेति वा अहमेतमुपास इति स यो हैतमेवमुपास्ते नाम्न्यस्यात्मा भवतीत्यधिदैवतमथाध्यात्मम् ॥ ९ ॥

In plain words

Bālāki said, "The person who is in the waters — him indeed I worship." Ajātaśatru said to him, "Do not draw me into talk about him. I worship him as the self of name." He who worships him thus becomes the self of name. So much with respect to the gods. Now with respect to the self.