Śatapatha Brāhmaṇa ("of a hundred paths") 4.2.2.10

4.2.2.10

pāhi yajñam pāhi yajñapatimiti | vācamevaitadutsṛṣṭāmāha gopāya yajñamiti pāhi yajñapatimiti vācamevaitadutsṛṣṭāmāha gopāya yajamānamiti yajamāno hi yajñapatirviṣṇustvāmindriyeṇa pātu viṣṇuṃ tvam pāhīti vācamevaitadutsṛṣṭāmāha yajño vai viṣṇuryajñastvāṃ vīryeṇa gopāyatviti viṣṇuṃ tvam pāhīti vācamevaitadutsṛṣṭāmāha yajñaṃ tvaṃ gopāyetyabhi savanāni pāhīti tadetaṃ grahamāha sarvāṇi hyeṣa savanāni prati

'Guard the sacrifice! guard the lord of the sacrifice!' whereby he utters freed speech, meaning to say, 'Protect the sacrifice! protect the sacrificer!' for the lord of the sacrifice is the sacrificer. 'May Vishnu-guard thee with his might! guard thou Vishnu!' whereby he utters freed speech--Vishnu being the sacrifice--'May the sacrifice protect thee with its power! protect thou the sacrifice!'--'Guard thou the Soma feasts all around!' whereby he means this very graha, because that belongs to all (three) Soma feasts.