Hiraṇyakaśipu had four wonderful, well-qualified sons, of whom the one named Prahlāda was the best. Indeed, Prahlāda was a reservoir of all transcendental qualities because he was an unalloyed devotee of the Personality of Godhead.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
तस्य दैत्यपतेः पुत्राश्चत्वारः परमाद्भुताः । प्रह्लादोऽभून्महांस्तेषां गुणैर्महदुपासकः
tasya daityapateḥ putrāścatvāraḥ paramādbhutāḥ | prahlādo'bhūnmahāṃsteṣāṃ guṇairmahadupāsakaḥ
SB 7.4.30