Shatapatha Brahmana 13.5.1.12

13.5.1.12

athāta āgnimārutam mūrdhānaṃ divo aratim pṛthivyā iti vaiśvānarīyaṃ śastvaikāhike nividaṃ dadhātyā rudrāsa indravantaḥ sajoṣasa iti mārutaṃ śastvaikāhike nividaṃ dadhātīmamūṣu vo atithimuṣarbudhamiti navarcaṃ jātavedasīyaṃ śastvaikāhike nividaṃ dadhāti tadyadaikāhikāni nividdhānāni bhavanti pratiṣṭhā vai jyotiṣtomaḥ pratiṣṭhāyā apracyutyai

Then as to the Âgnimâruta. Having recited the (hymn, VI, 7) to (Agni) Vaisvânara, 'The head of the sky, and the disposer of the earth...,' he inserts the Nivid in the (hymn, III, 3) of the one-day's sacrifice. Having recited the (hymn, V, 57) to the Maruts, 'Hither, O Rudras, come ye united with Indra...,' he inserts the Nivid in the (hymn, I, 87) of the one-day's sacrifice. Having recited the nine verses (VI, 15, 1-9) to Gâtavedas, 'This guest of yours, the early-waking...,' he inserts the Nivid in the (hymn, I, 143) of the one-day's sacrifice. And as to why the (hymns) of the one-day's sacrifice are used for inserting the Nivid, it is for the sake of his (the Sacrificer's) not being deprived of a firm foundation, for the Gyotishtoma is a foundation.