Jaiminīya (Talavakāra) Brāhmaṇa 1.195

1.195

sendreṇa vajreṇa vṛtraṃ pāpmānaṃ hanānīti
sendreṇa haiva vajreṇa dviṣantaṃ pāpmānaṃ bhrātṛvyaṃ hanti ya evaṃ veda
atho āhussaptadaśa eva kārya iti
pañcadaśo vai vajraḥ
indro vajrasyodyantā ṣoḍaśaḥ
prajāpatireva saptadaśaḥ
so'nuṣṭhātā so'bhigoptā so'bhivādayitā praharjahi māpakramīḥ iti
sendreṇa vajreṇa saprajāpatikena vṛtraṃ pāpmānaṃ hanānīti
sendreṇa haiva vajreṇa saprajāpatikena dviṣantaṃ pāpmānaṃ bhrātṛvyaṃ hanti ya evaṃ veda
atho āhurekaviṃśa eva kārya iti
sarvābhyo vā etaṃ saptabhyo hotrābhya indro vajraṃ niramimīta tisrastisra eva
hotrāyai
sa ekaviṃśaṣṣoḍaśī samapadyata
tenendro vṛtramahan
hanti dviṣantaṃ bhrātṛvyaṃ ya evaṃ veda
tadu hovāca yāmano bhrātalāyano virājo vā eṣa saṃpade ṣoḍaśī
vairājo vai ṣoḍaśī virājivirāji pratiṣṭhitaḥ
sa yatraivaitaṃ virājaṃ saṃpadyamānaṃ manyeta tadevaitena stotavyam

[Indra thinks:] 'With Indra along with the thunderbolt may I slay evil Vṛtra.' With Indra along with the thunderbolt he indeed slays his hostile, evil rival who knows thus. Now they also say: 'It should be made seventeenfold.' The fifteenfold is indeed the thunderbolt; Indra is the wielder of the thunderbolt, the sixteenth; Prajāpati himself is the seventeenth. He is the director, he the protector, he the prompter: 'Strike! Slay! Do not retreat!' [He thinks:] 'With Indra along with the thunderbolt, along with Prajāpati, may I slay evil Vṛtra.' With Indra along with the thunderbolt, along with Prajāpati, he indeed slays his hostile, evil rival who knows thus. Now they also say: 'It should be made twenty-one-fold.' Indra fashioned this thunderbolt from all seven offices of the Hotṛ, three from each office of the Hotṛ. That Ṣoḍaśin turned out twenty-one-fold. With it Indra slew Vṛtra. He slays his hostile rival who knows thus. Now on this point Yāmana Bhrātalāyana said: 'This Ṣoḍaśin is for the attainment of the Virāj. The Ṣoḍaśin belongs to the Virāj, established in Virāj after Virāj. Wherever he considers this to turn out to be the Virāj, just there he should chant with this.'