SB 7.4.36
gunair alam asankhyeyair
mahatmyam tasya sucyate
vasudeve bhagavati
yasya naisargiki ratih
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Who could list the innumerable transcendental qualities of Prahlada Maharaja? He had unflinching faith in Vasudeva, Lord Krsna [the son of Vasudeva], and unalloyed devotion to Him. His attachment to Lord Krsna was natural because of his previous devotional service. Although his good qualities cannot be enumerated, they prove that he was a great soul [mahatma].
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
In his prayers to the ten incarnations, Jayadeva Gosvami says, kesava dhrta-narahari-rupa jaya jagad-isa hare. Prahlada Maharaja was a devotee of Lord Nrsimha, who is Kesava, Krsna Himself. Therefore when this verse says vasudeve bhagavati, one should understand that Prahlada Maharaja’s attachment for Nrsimhadeva was attachment for Krsna, Vasudeva, the son of Vasudeva. Prahlada Maharaja, therefore, is described as a great mahatma. As the Lord Himself confirms in Bhagavad-gita (7.19):
bahunam janmanam ante
jñanavan mam prapadyate
vasudevah sarvam iti
sa mahatma sudurlabhah
“After many births and deaths, he who is actually in knowledge surrenders unto Me, knowing Me to be the cause of all causes and all that is. Such a great soul is very rare.” A great devotee of Krsna, the son of Vasudeva, is a great soul very rarely to be found. Prahlada Maharaja’s attachment for Krsna will be explained in the next verse. Krsna-graha-grhitatma. Prahlada Maharaja’s heart was always filled with thoughts of Krsna. Therefore Prahlada Maharaja is the ideal devotee in Krsna consciousness.