Śatapatha Brāhmaṇa ("of a hundred paths") 3.5.3.15

3.5.3.15

devā ha vai yajñaṃ tanvānāḥ | te 'surarakṣasebhya āsaṅgādbibhayāṃ cakrurvajro vā ājya ta etena vajreṇājyena dakṣiṇato nāṣṭrā rakṣāṃsyavāghnaṃstathaiṣāṃ niyānaṃ nānvavāyaṃstatho evaiṣa etena vajreṇājyena dakṣiṇato nāṣṭrā rakṣāṃsyavahanti tathāsya niyānaṃ nānvayanti tadyadvaiṣṇavībhyāmṛgbhyāṃ juhoti vaiṣṇavaṃ hi havirdhānam

Now, once on a time, the gods, while performing sacrifice, were afraid of an attack on the part of the Asura-Rakshas; and, the ghee being a thunderbolt, they kept off the evil spirits from the south by that thunderbolt, the ghee; and thus they came not after them on their way. And in like manner does he now keep off the evil spirits from the south by that thunderbolt, the ghee; and thus they do not come after him on his way. And the reason why he offers with two verses relating to Vishnu, is that the Soma-cart belongs to Vishnu.