Prahlāda Mahārāja was already educated in devotional life, but when his father sent him to those two sons of Śukrācārya to be educated, they accepted him at their school along with the other sons of the asuras.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
तौ राज्ञा प्रापितं बालं प्रह्लादं नयकोविदम् । पाठयामासतुः पाठ्यानन्यांश्चासुरबालकान्
tau rājñā prāpitaṃ bālaṃ prahlādaṃ nayakovidam | pāṭhayāmāsatuḥ pāṭhyānanyāṃścāsurabālakān
SB 7.5.2