तद्वैतद्ब्रह्मा प्रजापतय उवाच प्रजापतिर्मनवे मनु प्रजाभ्यस्तद्वैतदुद्दालकायारुणये ज्येष्ठाय पुत्राय पिता ब्रह्म प्रोवाच ॥
In plain words
This very truth Brahma imparted to Prajāpati, Prajāpati to Manu, and Manu to mankind. And this same truth a father imparted as Brahman to his eldest son, Uddālaka Āruṇi.
Close to the Sanskrit
That indeed, Brahma spoke to Prajāpati; Prajāpati to Manu; Manu to the subjects; and that indeed to Uddālaka Āruṇi, the eldest son, the father spoke forth Brahman.