Maitrayaniya Upanishad 7.10.3

7.10.3

tyunnatabudhnaṃ bhavati bījasyevocchūnatā vedasyādyāvasthārūpaṃ jāyata ityarthaḥ | tat udayati uṅgacchati aṅkura ivāntarnādarūpapraṇavākāraṃ bhavati, tataḥ krameṇocchvasatyucchvāsa iva dīrghasvareṇoccāraṇasthānaṃ prāpyākṣararūpamavatiṣṭhata ityarthaḥ | evamabhivyaktapraṇavākārabrahmatejorūpo vedo'jasraṃ nairantaryeṇa brahmadhīyālambaṃ, viśliṣṭapāṭhaḥ chāndasaḥ, brahmabuddherūpāsanātmikāyā ālambanamityarthaḥ | vāśabdāt brahmatattvabuddhyālambanaṃ cetyarthaḥ | adhikāribhedāt buddhidvayālambanatvavikalpārtho vā vāśabdaḥ | athaivā'syāmevāvasthāyāmetat tejaḥ praṇavamātrākāraṃ sat samīraṇe koṣṭhagate prāṇe ghoṣavati sahakāriṇi sampanne sati dūtiśeṣaḥ | prakāśaṃ prakṣipati tyajati iti prakāśaprakṣepakaḥ, jaṭharakuharacāryagnistasyauṣṭhyasthāne bhavaṃ prakāśaprakṣepakauṣṭhyasthānīyaṃ tantejo'nuprasaratītyuttaratrānvayaḥ | anuprasaraṇaprakāraṃ dṛṣṭāntena spaṣṭayati, etaditi | etadanuprasaraṇaṃ dhūmasyeva draṣṭavyaṃ, yathā dhūmo nabhasi samīraṇe vāyau vāti mati praśākhayaiva prakṛṣṭayā śākhayā śākhākārayā lekhayotkramyorddhadeśaṃ gatvā vṛkṣasya skandhāt skandhamanusarati tattatskandhairabhihanyamānastattadākāratāmaśnute, tathaitadbrahmatejo mūlādhāroparyagnimaṇḍale tatrasthenāgninā mantṛtte'bhivyaktaṃ ghoṣavatprāṇavāyunāgnau dhmyamāne tameva vāyumagniṃ