Śatapatha Brāhmaṇa ("of a hundred paths") 3.1.3.6

3.1.3.6

tasya saptadaśa sāmidhenyo bhavanti | upāṃśu devate yajati pañca prayājā bhavanti trayo 'nuyājāḥ saṃyājayanti patnīḥ sarvatvāyaiva samiṣṭayajureva na juhoti nedidaṃ dīkṣitavasanam paridhāya purā yajñasya saṃsthāyā antaṃ gacānītyānto hi yajñasya samiṣṭayajuḥ

There are seventeen kindling-verses for it. In a low voice he offers to the two deities. There are five fore-offerings and three after-offerings. For the sake of completeness they perform the patnîsamyâgas; but he offers no samishtayagus, lest, having put on that garment of the consecrated, he should reach the end of the sacrifice before its completion; for the samishtayagus is the end of the sacrifice.