niśamyātharvaṇaṁ dakṣaṁ pravargya-brahmavidyayoḥ; dadhyañcaṁ samupāgamya tam ūcatur athāśvinau; bhagavan dehi nau vidyām iti śrutvā sa cābravīt; karmaṇy avasthito 'dyāhaṁ paścād vakṣyāmi gacchatam; tayor nirgatayor eva śakra āgatya taṁ munim; uvāca bhiṣajor vidyāṁ mā vādīr aśvinor mune; yadi mad-vākyam ullaṅghya bravīṣi sahasaiva te; śiraś-chindyāṁ na sandeha ity uktvā sa yayau hariḥ; indre gate tathābhyetya nāsatyāv ūcatur dvijam; tan-mukhād indra-gaditaṁ śrutvā tāv ūcatuḥ punaḥ; āvāṁ tava śiraś chittvā pūrvam aśvasya mastakam; sandhāsyāvas tato brūhi tena vidyāṁ ca nau dvija; tasminn indreṇa sañchinne punaḥ sandhāya mastakam; nijaṁ te dakṣiṇāṁ dattvā gamiṣyāvo yathāgatam; etac chrutvā tadovāca dadhyaṅṅ ātharvaṇas tayoḥ pravargyaṁ brahma-vidyāṁ ca sat-kṛto 'satya-śaṅkitaḥ.
The great saint Dadhīci had perfect knowledge of how to perform fruitive activities, and he had advanced spiritual knowledge as well. Knowing this, the Aśvinī-kumāras once approached him and begged him to instruct them in spiritual science (brahma-vidyā). Dadhīci Muni replied, "I am now engaged in arranging sacrifices for fruitive activities. Come back some time later." When the Aśvinī-kumāras left, Indra, the King of heaven, approached Dadhīci and said, "My dear Muni, the Aśvinī-kumāras are only physicians. Please do not instruct them in spiritual science. If you impart the spiritual science to them despite my warning, I shall punish you by cutting off your head." After warning Dadhīci in this way, Indra returned to heaven. The Aśvinī-kumāras, who understood Indra's desires, returned and begged Dadhīci for brahma-vidyā. When the great saint Dadhīci informed them of Indra's threat, the Aśvinī-kumāras replied, "Let us first cut off your head and replace it with the head of a horse. You can instruct brahma-vidyā through the horse's head, and when Indra returns and cuts off that head, we shall reward you and restore your original head." Since Dadhīci had promised to impart brahma-vidyā to the Aśvinī-kumāras, he agreed to their proposal. Therefore, because Dadhīci imparted brahma-vidyā through the mouth of a horse, this brahma-vidyā is also known as Aśvaśira.