Śatapatha Brāhmaṇa ("of a hundred paths") 11.3.1.6

11.3.1.6

yo javiṣṭho bhuvaneṣu sa vidvānpravasanvide tathā tadasya kāvyaṃ tathā saṃtato agnibhiriti mana evaitadāha manasaivāsyānapaproṣitam bhavatīti

'He who is the swiftest in the worlds, that wise one is found staying abroad: thus (is manifested) his wisdom, thus he is kept up by his fires;'--he thereby means the mind: it is owing to his mind that there is no staying away from home on his part.