tam sannibhartsya kupitah
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The great saint Narada Muni continued: The great soul Prahlada Maharaja became silent after saying this to his teachers, Sanda and Amarka, the seminal sons of Sukracarya. These so-called brahmanas then became angry at him. Because they were servants of Hiranyakasipu, they were very sorry, and to chastise Prahlada Maharaja they spoke as follows.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The word sukra means “semen.” The sons of Sukracarya were brahmanas by birthright, but an actual brahmana is one who possesses the brahminical qualities. The brahmanas Sanda and Amarka, being seminal sons of Sukracarya, did not actually possess real brahminical qualifications, for they engaged as servants of Hiranyakasipu. An actual brahmana is very much satisfied to see anyone, not to speak of his disciple, become a devotee of Lord Krsna. Such brahmanas are meant to satisfy the supreme master. A brahmana is strictly prohibited from becoming a servant of anyone else, for that is the business of dogs and sudras. A dog must satisfy his master, but a brahmana does not have to satisfy anyone; he is simply meant to satisfy Krsna (anukulyena krsnanusilanam). That is the real qualification of a brahmana. Because Sanda and Amarka were seminal brahmanas and had become servants of such a master as Hiranyakasipu, they unnecessarily wanted to chastise Prahlada Maharaja.