Varahashrautasutra 2.2.3.3

2.2.3.3

imā me agnā iṣṭakā dhenavaḥ santvityabhimantrya śatarudriyaṃ juhotyarkaparṇenājakṣīreṇa gavīdhukāsaktūnkṛtvā ṣā vibhajyottarāparasyāmiṣṭakāyāmudaṅ tiṣṭhannātyadvohannagniṃ namaste rudra manyava iti prabhṛtinā namaḥ senābhyaḥ senānībhyaśca vo nama ityantena jānudaghne

Having addressed [them] with ‘May these bricks be milch cows for me, O Agni’, having made groats of gavīdhukā with goat's milk and dividing it into six parts, standing facing north, not overstepping the fire, he offers the Śatarudriya on the north-western brick with an arka leaf, knee-high, with [the section] beginning with ‘Homage to your wrath, O Rudra’ and ending with ‘Homage to the armies and homage to you commanders of armies’.