By regular attendance in classes on the Bhāgavatam and by rendering of service to the pure devotee, all that is troublesome to the heart is almost completely destroyed, and loving service unto the Personality of Godhead, who is praised with transcendental songs, is established as an irrevocable fact.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
नष्टप्रायेष्वभद्रेषु नित्यं भागवतसेवया । भगवत्युत्तमश्लोके भक्तिर्भवति नैष्ठिकी
naṣṭaprāyeṣvabhadreṣu nityaṃ bhāgavatasevayā | bhagavatyuttamaśloke bhaktirbhavati naiṣṭhikī
SB 1.2.18