Śatapatha Brāhmaṇa ("of a hundred paths") 7.3.2.11

7.3.2.11

tamuttarādhenāgneḥ | antareṇa pariśritaḥ prāñcaṃ nayanti tatprācyai diśaḥ pāpmānamapahanti taṃ dakṣiṇā taddakṣiṇāyai diśaḥ pāpmānamapahanti tam pratyañcaṃ tatpratīcyai diśaḥ pāpmānamapahanti tamudañcaṃ tadudīcyai diśaḥ pāpmānamapahanti sarvābhya evaitaddigbhyo rakṣāṃsi nāṣṭrā apahatyāthainamudañcam prāñcam prasṛjati tasyokto bandhuḥ

They lead it eastward on the left (north) side of the altar, inside the enclosing-stones, whereby they ward off evil from the eastern region; then southward, whereby they ward off evil from the south; then westward, whereby they ward off evil from the western region; then northward, whereby they ward off evil from the northern region. Having thus warded off the Rakshas, the fiends, from all the regions, he sets it (the horse) free towards northeast: the significance of this has been explained.