The works of Ādi Śaṅkarācārya

Chāndogyopaniṣadbhāṣyam

Verse 210

अथ हैनमाहवनीयोऽनुशशास प्राण आकाशो द्यौर्विद्युदिति य एष विद्युति पुरुषो दृश्यते सोऽहमस्मि स एवाहमस्मीति ॥ १ ॥

In plain words

Then the Āhavanīya fire instructed him: Breath, space, the sky, lightning. The person who is seen in lightning—that person is I; I indeed am that person.

Close to the Sanskrit

Now the Āhavanīya fire instructed him: breath, space, sky, lightning. He who is seen as a person in lightning, I am he, I indeed am he.