Srimad Bhagavat Mahatmya, meaning The Glories of Srimad Bhagavatam, is the best source of knowing the importance and greatness of Srikrishna katha. This consists of the six chapters of the Bhagavata-mahatmya found in the Uttara-khanda of the Padma Purana (Chapters 193 to 198). The reading of Mahatmyam gives us a clear idea about the greatness and impact of reading Bhagavatam as a bhakti and spiritual treatise.
Srimad Bhagavatam is the accomplished fruit of the Veda tree and bears the capacity to fulfill all desires. The Saptaha Parayana or hearing Srimad Bhagavatam in seven days (Saptaha-yajna) is the means for removal of distress and attaining higher spiritual status. The core devotees of the Bhagavan, being free from all material wishes, do not indulge in such recitation or rituals, but they use the Saptaha patha for preaching to the masses. The greatness of this text has been eulogized in many Puranas like Garuda, Brahma, Brahmanda, Markandaya, Vayu, Agni, Skanda, Padma. The Padma Purana describes glory and greatness in a unique way.
The Puranas sometimes instruct through the indirect method of story-telling (paroksha-vada). This does not mean, however, that this narration is a fable. It is factual, but there is a moral to the story. The good effects enlisted also do happen in our lives.
Bhagavatam is the king of all Puranas that removes ignorance, confers the pinnacle of knowledge and devotion in the Lord, and also vairagya or dispassion in all worldly attractions and illusions that keep entangling with samsara the cycle of death and birth. It brings happiness. The amrita or the nectar that was received after Kshirasamudra mathana or churning of Milky Way is not comparable to the greatness of Srimad Bhagavatham.