Śatapatha Brāhmaṇa ("of a hundred paths") 3.5.3.17

3.5.3.17

atha vācayati | prācī pretamadhvaraṃ kalpayantī ityadhvaro vai yajñaḥ prācī pretaṃ yajñaṃ kalpayantī ityevaitadāhordhvaṃ yajñaṃ nayatam mā jihvaratamityūrdhvamimaṃ yajñaṃ devalokaṃ nayatamityevaitadāha mā jihvaratamiti tadetasmā ahvalāmāśāste samudgṛhyeva pravartayeyuryathā notsarjetāmasuryā vā eṣā vāgyākṣe nedihāsuryā vāgvadāditi yadyutsarjetām

He makes (the sacrificer) say, 'Go ye both forward, furthering the cult!' The cult, namely, is the sacrifice: 'go ye both forward, furthering the sacrifice' he thereby means to say. 'Convey ye the sacrifice upward; lead it not astray!' whereby he means to say, 'convey this sacrifice upward to the world of the gods;' and by saying 'lead it not astray,' he prays for this (sacrificer) that he may not stumble. Let them wheel (the carts) forward, as it were lifting them, so that they may not creak; for of the Asuras is that voice which is in the axle: 'Lest the Asuras’ voice should speak here!' so he thinks. But if they should creak,--