SB 7.7.1
sri-narada uvaca
evam daitya-sutaih prsto
maha-bhagavato ’surah
uvaca tan smayamanah
smaran mad-anubhasitam
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Narada Muni said: Although Prahlada Maharaja was born in a family of asuras, he was the greatest of all devotees. Having thus been questioned by his class friends, the sons of the asuras, he remembered the words spoken to him by me and replied to his friends as follows.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
When he was in the womb of his mother, Prahlada Maharaja listened to the words of Narada Muni. One cannot imagine how the baby in embryo could hear Narada, but this is spiritual life; progress in spiritual life cannot be obstructed by any material condition. This is called ahaituky apratihata. Reception of spiritual knowledge is never checked by any material condition. Thus Prahlada Maharaja, from his very childhood, spoke spiritual knowledge to his class friends, and certainly it was effective, although all of them were children.