Srimad Bhagavatam Canto 07, Chapter 04, Text 43

SB 7.4.43

tasmin maha-bhagavate
 maha-bhage mahatmani
hiranyakasipu rajann
 akarod agham atmaje
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
My dear King Yudhisthira, the demon Hiranyakasipu tormented this exalted, fortunate devotee, although Prahlada was his own son.
 
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
When a demon like Hiranyakasipu, despite his elevated position due to severe austerities, begins to tease a devotee, he begins falling down, and the results of his austerities dwindle. One who oppresses a pure devotee loses all the results of his austerities, penances and pious activities. Since Hiranyakasipu was now inclined to chastise his most exalted devotee son, Prahlada Maharaja, his opulences began dwindling.
Srimad Bhagavatam Canto 07, Chapter 04, Text 42
Srimad Bhagavatam Canto 07, Chapter 04, Text 44