Śatapatha Brāhmaṇa ("of a hundred paths") 1.4.2.10

1.4.2.10

praṇīryajñānāṃ rathīradhvarāṇāmiti | etena vai sarvānyajñānpraṇayanti ye ca pākayajñā ye cetare tasmādāha praṇīryajñānāmiti

Further, 'The leader of oblations (yagña), the carrier of (Soma-)sacrifices (adhvara),' for through him they lead forward all oblations, both the domestic oblations and the others: this is why he says 'the leader of oblations.'