Jaiminīya (Talavakāra) Brāhmaṇa 2-3.20

2-3.20

piṇḍāḥ piṇḍā iva hi bhavantyakratāḥ
yathāṅgameva stotavyam
te haivāmuṣmim̐lloke sāṅgāssatanavo'mṛtāssaṃbhavanti
atha haike sakṛdeva śīrṣṇe hiṃkurvanti parāṅetadyacchira iti vadantaḥ
tristriritarebhyo'ṅgebhyaḥ
te trayodaśa hiṃkārāssaṃpadyante
evaṃ trayodaśasya māsa upāptiriti
tadu ha śaśvanna tathā
trireva śīrṣṇe hiṃkurvantastristriritarebhyo'ṅgebhyaḥ
te pañcadaśa hiṃārāssaṃpadyante
pañcadaśo vā indraḥ
ṣandraṃ mahāvrataṃ tattatsalakṣma kriyate

for, lacking ritual form, they become like mere lumps. One should chant limb by limb. They indeed come into being in that world endowed with limbs, endowed with bodies, immortal. Now some make the sound hiṃ only once for the head, saying: "The head is facing away from this [chant]." Three times each for the other limbs. Those make thirteen hiṃ-sounds. "Thus is the attainment of the thirteenth month." But that is certainly not so. Making the sound hiṃ three times for the head, three times each for the other limbs, those make fifteen hiṃ-sounds. Indra is fifteen-fold; the Mahāvrata belongs to Indra: that is made possessed of its characteristic sign.