O chief of the Kuru dynasty, the Vedic wisdom became manifested from the mouth of the virāṭ, the gigantic form. Those who are inclined to this Vedic knowledge are called brāhmaṇas, and they are the natural teachers and spiritual masters of all the orders of society.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
मुखतोऽवर्तत ब्रह्म पुरुषस्य कुरूद्वह । यस्तून्मुखत्वाद्वर्णानां मुख्योऽभूद्ब्राह्मणो गुरुः
mukhato'vartata brahma puruṣasya kurūdvaha | yastūnmukhatvādvarṇānāṃ mukhyo'bhūdbrāhmaṇo guruḥ
SB 3.6.30