Yāska's Nirukta 82.7

82.7

"dvitā (19)"-ityanavagatam | "dvaidham"-ityavagamaḥ || "yastvaddhotā̱ pūrvo̍ agne̱ yajī̍yāndvi̱tā ca̱ sattā̍ sva̱dhayā̍ ca śa̱mbhuḥ | tasyānu̱dharma̱ṃ praya̍jā cikitvo'thā̍ no dhā adhva̱raṃ de̱vavī̍tau || (ṛ0 saṃ0 3, 1, 17, 5)"-iti || katasya vaiśvāmitrasyeyamārṣam | triṣṭup | prātaranuvākāśvinayoḥ śasyate || he bhagavan ! 'agne !' pṛthivīsthāna ! 'tvat' tvattaḥ, 'yaḥ' 'pūrvaḥ' 'hotā' madhyamasthānau vāyuḥ, asāvapi hi dūto devānāmauti śrūyate,-"ā dū̱to a̱gnima̍bharad vivasva̱taḥ"-iti vaidyuto'gniriti kecinmanyante | 'yajīyāna' yaṣṭrataraḥ | "dvitā ca sattā" "dvaidhaṃ" ca yasya vidyamānatā,-"madhyame ca sthāne" vaidyutabhāvena, "uttame ca" sthāne sūryabhāvena | "svadhayā ca" annena, sarvabhūtānāṃ varṣaṇadvāreṇa | yaḥ 'śambhuḥ' "sukhabhūḥ" sukhasya bhāvayitā | tasya kim ? iti | ucyate- 'tasya anudharma' tasya vāyorvṛttilābhamanvātmano dīptilakṣaṇāṃ vṛttimatilābhamāpnuvan, "vāyurvā agnestejaḥ, tasmād vāyuragnimanveti-iti ha vijñāyate" | he agne ! 'prayaja' prakarṣeṇa yaja, devān | he 'cikitvaḥ' cikittvan ! jñānanannityarthaḥ | 'atha' evam, 'naḥ' asmākaṃ yāgaṃ kurvan, tvaṃ śṛṇu, yat kuruṣva | 'dhā adhvaraṃ' dhāraya yajñam | 'devavītau' devatarpaṇāyetyarthaḥ || evamatra śabdasārūpyādarthopapatteśca "dvitā"-ityayaṃ dvaidhamityevamupapadyate |