Srimad-Bhagavatam: Canto 7 - Chapter 1 - Verse 48

Sanskrit:

श्रीयुधिष्ठिर उवाचविद्वेषो दयिते पुत्रे कथमासीन्महात्मनि ।ब्रूहि मे भगवन्येन प्रह्लादस्याच्युतात्मता ॥ ४८ ॥

ITRANS:

śrī-yudhiṣṭhira uvācavidveṣo dayite putrekatham āsīn mahātmanibrūhi me bhagavan yenaprahlādasyācyutātmatā

Translation:

Mahārāja Yudhiṣṭhira inquired: O my lord, Nārada Muni, why was there such enmity between Hiraṇyakaśipu and his beloved son Prahlāda Mahārāja? How did Prahlāda Mahārāja become such a great devotee of Lord Kṛṣṇa? Kindly explain this to me.

Purport:

All the devotees of Lord Kṛṣṇa are called acyutātmā because they follow in the footsteps of Prahlāda Mahārāja. Acyuta refers to the infallible Lord Viṣṇu, whose heart is always infallible. Because the devotees are attached to the Infallible, they are called acyutātmā.