SB 7.5.29

śrī-nārada uvāca
guruṇaivaṁ pratiprokto
 bhūya āhāsuraḥ sutam
na ced guru-mukhīyaṁ te
 kuto ’bhadrāsatī matiḥ
Synonyms: 
śrī-nāradaḥ uvāca — Nārada Muni said; guruṇā — by the teacher; evam — thus; pratiproktaḥ — being answered; bhūyaḥ — again; āha — said; asuraḥ — the great demon, Hiraṇyakaśipu; sutam — unto his son; na — not; cet — if; guru-mukhī — issued from the mouth of your teacher; iyam — this; te — your; kutaḥ — from where; abhadra — O inauspicious one; asatī — very bad; matiḥ — inclination.
Translation: 
Śrī Nārada Muni continued: When Hiraṇyakaśipu received this reply from the teacher, he again addressed his son Prahlāda. Hiraṇyakaśipu said: You rascal, most fallen of our family, if you have not received this education from your teachers, where have you gotten it?
Purport: 

Śrīla Viśvanātha Cakravartī Ṭhākura explains that devotional service is actually bhadrā satī, not abhadra asatī. In other words, knowledge of devotional service can be neither inauspicious nor contrary to etiquette. To learn devotional service is the duty of everyone. Therefore the spontaneous education of Prahlāda Mahārāja is supported as auspicious and perfect.