Manava Dharmashastra 1.97

1.97

brāhmaṇeṣu ca vidvāṃso vidvatsu kṛtabuddhayaḥ
kṛtabuddhiṣu kartāraḥ kartṛṣu brahmavedinaḥ //

Of Brahmanas, those learned (in the Veda); of the learned, those who recognise (the necessity and the manner of performing the prescribed duties); of those who possess this knowledge, those who perform them; of the performers, those who know the Brahman.