Maitrayaniya Upanishad 2.5.8

2.5.8

svabhāvamātmānaṃ prāsuvat prasūtavān uṣṇarūpeṇābhivyakta ityarthaḥ | dvaivoṣṇyamiti sandhiścchāndasaḥ | yadvā etayorantaraṃ madhyaṃ mūlādhāradeśastasmāt prāṇāpānābhyāṃ pārśvagatābhyāṃ dhamyamānādeva na sthānāntarāditi yāvat | auṣṇyaṃ prāsuvaditi pūrvavat | yadidamauṣṇyaṃ sa puruṣo jīvo dehasyāgnirūpeṇa dhārayitā, ūṣmarūpātmāvasthāne hi jīvatīti prasiddhiḥ, tadapagame ca maraṇaprasiddhiḥ | tathā ca śrutyantaram‘uṣṇo jīviṣyan śītomariṣyan’ iti | athaivaṃ sati yaḥ puruṣa ātmā so'gnirayaṃ nayatītyagraṇīragnirucyate | ayaṃ hi sarvadhātujātaṃ pacannagraṃ nayati ato'gniḥ | vaiśvānara iti cāyamucyate viśvaṃ sarvaṃ naraśabdopalakṣitaṃ dehādikaṃ nayatyunnamaya tīti viśvānaro viśvānara eva vaiśvānara iti | etadeva puruṣāgnyorekatvamihoktaṃ siddhavatkṛtya śākhāntare jāṭharasyāgnerūpāsanamuktaṃ tadiha prasaṅgādupadiśati“anyatrāpyuktaṃ ॰ śṛṇoti” iti | anyatra bṛhadāraṇyake'pītyarthaḥ | ayamagnivaiśvānaraḥ puruṣākhyo yo'yaṃ prasiddho'ntaḥpuruṣe puruṣaḥ śarīraṃ śarīramadhye | tatsadbhāve kāryaliṅgakaṃ pramāṇamāha, yena puruṣāntaḥsthenedaṃ vakṣyamāṇamannaṃ pacyate pānasyāpyupalakṣaṇaṃ. metat | kiṃ tadannaṃ tadāha yadidamadyate'viśeṣeṇa