This verse gives evidence confirming the statement of Bhagavad-gita that the orders of societybrahmana, ksatriya, vaisya and sudraare calculated in terms of qualities and activities (guna-karma-vibhagasah). All the descendants of Ajamidha, who was a ksatriya, became brahmanas. This was certainly because of their qualities and activities. Similarly, sometimes the sons of brahmanas or ksatriyas become vaisyas (brahmana-vaisyatam gatah). When a ksatriya or brahmana adopts the occupation or duty of a vaisya (krsi-go-raksya-vanijyam [Bg. 18.44]), he is certainly counted as a vaisya. On the other hand, if one is born a vaisya, by his activities he can become a brahmana. This is confirmed by Narada Muni. Yasya yal-laksanam proktam. The members of the varnas, or social ordersbrahmana, ksatriya, vaisya and sudramust be ascertained by their symptoms, not by birth. Birth is immaterial; quality is essential.