Kaṭha Upaniṣad 2.17.p3

2.17.p3

ā.bhā. - yadālambya samāśritya paraṃbrahma, devatāntaraṃ samupāsyate, tadālambanam viṣayaḥ ityetat | yathā gāyatrīṃ dvādaśākṣaramapyaṣṭākṣaraṃ vā samālambya paramapuruṣaḥ upāsyate kenacit, kenacittu oṃkāra evālambyate tadupāsane, ataḥ gāyatryāderiva oṃkāro'pi ālambanam | evaṃ bahuṣu ālambeṣu satsvapi, etat - oṃkārarūpam ālambanam | ālambanāntarāpekṣayā śreṣṭhaṃ dhyānādikriyāsu | ata eva etat oṃkārarūpaṃ ālambanaṃ yasya, tādṛśaṃ dhyānādikam, anyālambanadhyānādyapekṣayā, param - utkṛṣṭam | etat - oṃkārarūpameva paramapuruṣopāsane, ālambanaṃ jñātvā - samyagnirṇīya tadālambanakopāsanavidhānadvārā, brahmaloke - brahmaṇaḥ śrīrāmākhyasya, loke - sāketākhye, mahīyate - pūjyate, satkārapātraṃ bhavati iti | atra om ityanenaivākṣareṇa paramapuruṣamabhidhyāyīta (pra.u.5-5) ityādi śrutiśca bhavati oṃkārālambanakaparamapuruṣadhyānavidhāyinī iti anusandheyam |