Muṇḍaka Upaniṣad 3.2.6

3.2.6

vedāntavijñānasuniścitārthāḥ sannyāsayogād yatayaḥ śuddhasattvāḥ.
te brahmalokeṣu parāntakāle parāmṛtāḥ parimucyanti sarve.

6. They who have ascertained the meaning of the Vedānta-
knowledge,
Ascetics (*yati*) with natures purified through the application of
renunciation (*saṃnyāsa-yoga*)—
They in the Brahma-worlds at the end of time
Are all liberated beyond death.