Śatapatha Brāhmaṇa ("of a hundred paths") 3.1.3.13

3.1.3.13

śareṣīkayānakti | vajro vai śaro virakṣastāyai satūlā bhavatyamūlaṃ vā idamubhayataḥ paricinnaṃ rakṣo 'ntarikṣamanucarati yathāyam puruṣo 'mūla ubhayataḥ paricinno 'ntarikṣamanucarati tadyatsatūlā bhavati virakṣastāyai

He anoints (the eyes) with a reed-stalk, for the reed is a thunderbolt. It is one with a tuft, in order to chase away the evil spirits. For rootless, indeed, and unfettered on both sides, the Rakshas roams along the air; even as man here roams along the air, rootless and unfettered on both sides: the reason, then, why it is (a reed-stalk) with a tuft, is to chase away the evil spirits.