Srimad-Bhagavatam: Canto 9 - Chapter 1 - Verse 21

Sanskrit:

अजमीढो द्विमीढश्च पुरुमीढश्च हस्तिन: ।अजमीढस्य वंश्या: स्यु: प्रियमेधादयो द्विजा: ॥ २१ ॥

ITRANS:

ajamīḍho dvimīḍhaś capurumīḍhaś ca hastinaḥajamīḍhasya vaṁśyāḥ syuḥpriyamedhādayo dvijāḥ

Translation:

From King Hastī came three sons, named Ajamīḍha, Dvimīḍha and Purumīḍha. The descendants of Ajamīḍha, headed by Priyamedha, all achieved the position of brāhmaṇas.

Purport:

This verse gives evidence confirming the statement of Bhagavad-gītā that the orders of society — brāhmaṇa, kṣatriya, vaiśya and śūdra — are calculated in terms of qualities and activities (guṇa-karma-vibhāgaśaḥ). All the descendants of Ajamīḍha, who was a kṣatriya, became brāhmaṇas. This was certainly because of their qualities and activities. Similarly, sometimes the sons of brāhmaṇas or kṣatriyas become vaiśyas (brāhmaṇa-vaiśyatāṁ gatāḥ). When a kṣatriya or brāhmaṇa adopts the occupation or duty of a vaiśya (kṛṣi-gorakṣya-vāṇijyam), he is certainly counted as a vaiśya. On the other hand, if one is born a vaiśya, by his activities he can become a brāhmaṇa. This is confirmed by Nārada Muni. Yasya yal-lakṣaṇaṁ proktam. The members of the varṇas, or social orders — brāhmaṇa, kṣatriya, vaiśya and śūdra — must be ascertained by their symptoms, not by birth. Birth is immaterial; quality is essential.