Śatapatha Brāhmaṇa ("of a hundred paths") 13.1.3.7

13.1.3.7

sāvitryā eveṣṭeḥ purastādanudrutya sakṛdeva rūpāṇyāhavanīye juhotyāyatana evāhutīrjuhoti nāsmai bhrātṛvyaṃ janayati yajñamukhe-yajñamukhe juhoti yajñasya saṃtatyā avyavacedāya

Prior to the (first) oblation to Savitri, he (the Adhvaryu) offers, once only, (the oblations relating to) the Forms in the Âhavanîya, whilst going rapidly over (the formulas): he thus offers the oblations at his (the Sacrificer's) resting-place, and raises no rival for him. He offers at each opening of sacrifice, for the continuity and uninterrupted performance of the sacrifice.