Śatapatha Brāhmaṇa ("of a hundred paths") 4.4.5.14

4.4.5.14

athāparaṃ caturgṛhītamājyaṃ gṛhītvā | āśrāvyāha samidho yajeti so 'pabarhiṣaścaturaḥ prayājānyajati prajā vai barhirvaruṇyo vā avabhṛtho netprajā varuṇo gṛhṇāditi tasmādapabarhiṣaścaturaḥ prayājānyajati

Then, having taken ghee a second time in four ladlings, and having called for the (Âgnîdhra's) Sraushat, he says, 'Pronounce the offering prayer to the Kindling-sticks!' He offers four fore-offerings, omitting that to the Barhis --the Barhis being offspring, and the expiatory bath belonging to Varuna--lest Varuna should seize upon his offspring. This is why he offers four fore-offerings, omitting that to the Barhis.