Shatapatha Brahmana 8.5.1.15

8.5.1.15

atha ye abhitaḥ | tau bāhū sa yo 'syābhitaḥ pāpmāsīdbāhubhyāṃ tamapāhata tathaivaitadyajamāno yo 'syābhitaḥ pāpmā bhavati bāhubhyāmeva tamapahate

And the two on both sides (of the spine) are the two arms: whatever evil there was sideways of him, that he drove away with his arms; and in like manner does this Sacrificer now drive away with his arms whatever evil there is sideways of him.