Muṇḍaka Upaniṣad 1.2.11

1.2.11

tapaḥśraddhe ye hy upavasanty araṇye śāntā vidvāṃso bhaikṣacaryāṃ carantaḥ.
sūryadvāreṇa te virajāḥ prayānti yatrāmṛtaḥ sa puruṣo hy avyayātmā.

11. They who practise austerity (_tapas_) and faith (_śraddhā_) in the forest,
The peaceful (_śānta_) knowers who live on alms,
Depart passionless (_vi-rāga_) through the door of the sun,
To where is that immortal Person (Purusha), e'en the imperishable Spirit (Ātman).