Praśna Upaniṣad ("Six Questions") 5.4

5.4

athayadidvimātreṇamanasisaṃpadyateso'ntarikṣaṃyajurbhirunnīyatesomalokam
sa somaloke vibhūtimanubhūya punarāvartate

4. Now, if he is united in mind with two elements [namely *a* + *u*], he is led by the Yajus formulas to the intermediate space, to the world of the moon. Having experienced greatness in the world of the moon, he returns hither again.

5.4.p1

yaḥ punaretaṃ trimātreṇomityetenaivākṣareṇa paraṃ puruṣamabhidhyāyīta sa tejasi sūrye

5. Again, he who meditates on the highest Person (Purusha) with the three elements of the syllable *Om* [namely *a* + *u* + *m*], is united with brilliance (*tejas*) in the sun. As a snake is freed from its skin, even so, verily, is he freed from sin (*pāpman*). He is led by the Sāman chants to the world of Brahma. He beholds the Person that dwells in the body and that is higher than the highest living complex. As to this there are these two verses (*śloka*):—

5.4.p2

saṃpannaḥ