Śatapatha Brāhmaṇa ("of a hundred paths") 3.5.3.11

3.5.3.11

sa juhoti | yuñjate mana uta yuñjate dhiya iti manasā ca vai vācā ca yajñaṃ tanvate sa yadāha yuñjate mana iti tanmano yunaktyuta yuñjate dhiya iti tadvācaṃ yunakti dhiyādhiyā hyetayā manuṣyā jujyūṣantyanūkteneva prakāmodyeneva gāthābhiriva tābhyāṃ yuktābhyāṃ yajñaṃ tanvate

He offers with the text (Vâg. S. V, 14; Rig-veda V, 81, 1), 'They harness the mind and they harness the thoughts'--with the mind and with speech they truly perform the sacrifice. When he says, 'They harness the mind,' he harnesses the mind; and when he says, 'and they harness the thoughts (dhî),' he harnesses speech; for it is thereby that people seek to make their living in accordance with their respective intelligence (dhî), either by reciting (the Veda), or by readiness of speech, or by songs,--with these two thus harnessed they perform the sacrifice.