The Mukhya Upaniṣads

Aitareya · Adhyāya 1 · Khaṇḍa 3 · The Search for Food, and the Discovery of Who Asks

Passage 13

स जातो भूतान्यभिव्यैख्यत्किमिहान्यं वावदिषदिति ।स एतमेव पुरुषं ब्रह्म ततममपश्यदिदमदर्शमिती ३ ॥ १३ ॥

In plain words

Having been born, he perceived the beings distinctly, [thinking] 'what else here would I speak of?' He saw this very Person as Brahman, the most pervasive: 'I have seen this.'