156
Śrīmad-Bhāgavatam
[Canto 6, Ch. 9]
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.
TEXT 53
दध्यङ्ङायर्वणस्त्वष्ट्रे वमभिधं मदात्मकम् । विश्वरूपाय यत् प्रादात् त्वष्टा यत् त्वमधास्ततः ॥५३॥
dadhyaṅṅ ātharvaṇas tvaṣṭre varmābhedyaṁ mad-ātmakam viśvarūpāya yat prādāt tvaṣṭā yat tvam adhās tataḥ
dadhyaṅ —Dadhyañca;  ātharvaṇaḥ —the son of Atharvā;  tvaṣṭre —unto Tvaṣṭā;  varma —the protective covering known as Nārāyaṇa-kavaca;  abhedyam —invincible;  mat-ātmakam —consisting of Myself;  viśvarūpāya —unto Viśvarūpa;  yat —which;  prādāt —delivered;  tvaṣṭā —Tvaṣṭā;  yat —which;  tvam —you;  adhāḥ —received;  tataḥ —from him.
TRANSLATION
Dadhyañca’s invincible protective covering known as the Nārāyaṇa-kavaca was given to Tvaṣṭā, who delivered it to his son Viśvarūpa, from whom you have received it. Because of this Nārāyaṇa-kavaca, Dadhīci’s body is now very strong. You should therefore beg him for his body.