5. Kaivalya Upaniṣad on Brahman (Introduction)

[...] Kaivalya Upaniṣad verse 1

Āśvalāyana approached the Lord Parameṣṭhi (Brahmā) and said: Teach, O Lord, the knowledge of Brahman, the highest, always cultivated by the good, hidden and by which a wise man drives away instantly all the sins and reaches the Puruṣa higher than the high. And to him, Brahma said, “Know (this) by means of faith, devotion and meditation. Not by work, nor by progeny, nor by wealth, but by renunciation, some attained immortality. Higher than heaven, seated in the cave (Buddhi), that shines, (which) the self-controlled attain -the self-controlled, who being of pure minds have well ascertained the Reality, by the knowledge of Vedānta, and through Sannyāsa or renunciation. In the sphere of Brahma, at the time of cosmic dissolution, they all get liberated from the highest (apparent) immortality of the manifested universe.^[1]