Śatapatha Brāhmaṇa ("of a hundred paths") 4.6.6.1

4.6.6.1

devā ha vai yajñaṃ tanvānāḥ | te 'surarakṣasebhya āsaṅgādbibhayāṃ cakruste hocuḥ ko no dakṣiṇata āsiṣyate 'thābhaye 'nāṣṭra uttarato yajñamupacariṣyāma iti

Now once on a time the gods, while performing sacrifice, were afraid of an attack from the Asura-Rakshas. They said, 'Who of us shall sit on the south side; we will then enter upon the sacrifice on the north side in a place free from danger and injury.'