268
Śrīmad-Bhāgavatam
[Canto 9, Ch. 16]
Paraśurāma we can understand that although Paraśurāma belonged to the brahminical group, he circumstantially had to work as a  kṣatriya . Later, after finishing his work as a  kṣatriya , he again became a  brāhmaṇa  and returned to Mahendra-parvata. Similarly, we can see that although Viśvāmitra was born in a  kṣatriya  family, by austerities and penances he achieved the position of a  brāhmaṇa . These histories confirm the statements in  śāstra  that a  brāhmaṇa  may become a  kṣatriya , a  kṣatriya  may become a  brāhmaṇa  or  vaiśya , and a  vaiśya  may become a  brāhmaṇa , by achieving the required qualities. One's status does not depend upon birth. As confirmed in  Śrīmad-Bhāgavatam  (7.11.35) by Nārada:
yasya yal lakṣaṇaṁ proktaṁ puṁso varṇābhivyañjakam yad anyatrāpi dṛśyeta tat tenaiva vinirdiśet
“If one shows the symptoms of being a  brāhmaṇa ,  kṣatriya ,  vaiśya  or  śūdra , even if he has appeared in a different class, he should be accepted according to those symptoms of classification.” To know who is a  brāhmaṇa  and who is a  kṣatriya , one must consider a man's quality and work. If all the unqualified  śūdras  become so-called  brāhmaṇas  and  kṣatriyas , social order will be impossible to maintain. Thus there will be discrepancies, human society will turn into a society of animals, and the situation all over the world will be hellish.
TEXT 29
विश्वामित्रस्य चैवासन् पुत्रा एकशतं नृप । मध्यमस्तु मधुच्छन्दा मधुच्छन्दस एव ते ॥२९॥
viśāmitrasya caivāsan putrā eka-śataṁ nṛpa madhyamas tu madhucchandā madhucchandasa eva te
viśvāmitrasya —of Viśvāmitra;  ca —also;  eva —indeed;  āsan —there were;  putrāḥ —sons;  eka-śataṁ —101;  nṛpa —O King Parikṣit;