Kaṭha Upaniṣad 96

96

taṃ durdarśaṃ gūḍham anupraviṣṭaṃ guhāhitaṃ gahvareṣṭhaṃ purāṇam /
adhyātmayogādhigamena devaṃ matvā dhīro harṣaśokau jahāti ///1,2.12 //

12. Contemplating with a concentrated mind, weaned from all external objects on the atman, ancient, hard to see, lodged in the inmost recess, located in intelligence, and seated amidst miserable surroundings, the intelligent man renounces joy and grief.