SB 1.5.16

vicakṣaṇo ’syārhati vedituṁ vibhor
 ananta-pārasya nivṛttitaḥ sukham
pravartamānasya guṇair anātmanas
 tato bhavān darśaya ceṣṭitaṁ vibhoḥ
Synonyms: 
vicakṣaṇaḥ — very expert; asya — of him; arhati — deserves; veditum — to understand; vibhoḥ — of the Lord; ananta-pārasya — of the unlimited; nivṛttitaḥ — retired from; sukham — material happiness; pravartamānasya — those who are attached to; guṇaiḥ — by the material qualities; anātmanaḥ — devoid of knowledge in spiritual value; tataḥ — therefore; bhavān — Your Goodness; darśaya — show the ways; ceṣṭitam — activities; vibhoḥ — of the Lord.
Translation: 
The Supreme Lord is unlimited. Only a very expert personality, retired from the activities of material happiness, deserves to understand this knowledge of spiritual values. Therefore those who are not so well situated, due to material attachment, should be shown the ways of transcendental realization, by Your Goodness, through descriptions of the transcendental activities of the Supreme Lord.
Purport: 

Theological science is a difficult subject, especially when it deals with the transcendental nature of God. It is not a subject matter to be understood by persons who are too much attached to material activities. Only the very expert, who have almost retired from materialistic activities by culture of spiritual knowledge, can be admitted to the study of this great science. In the Bhagavad-gītā it is clearly stated that out of many hundreds and thousands of men only one person deserves to enter into transcendental realization. And out of many thousands of such transcendentally realized persons, only a few can understand the theological science specifically dealing with God as a person. Śrī Vyāsadeva is therefore advised by Nārada to describe the science of God directly by relating His transcendental activities. Vyāsadeva is himself a personality expert in this science, and he is unattached to material enjoyment. Therefore he is the right person to describe it, and Śukadeva Gosvāmī, the son of Vyāsadeva, is the right person to receive it.

Śrīmad-Bhāgavatam is the topmost theological science, and therefore it can react on the laymen as medicinal doses. Because it contains the transcendental activities of the Lord, there is no difference between the Lord and the literature. The literature is the factual literary incarnation of the Lord. So the laymen can hear the narration of the activities of the Lord. Thereby they are able to associate with the Lord and thus gradually become purified from material diseases. The expert devotees also can discover novel ways and means to convert the nondevotees in terms of particular time and circumstance. Devotional service is dynamic activity, and the expert devotees can find out competent means to inject it into the dull brains of the materialistic population. Such transcendental activities of the devotees for the service of the Lord can bring a new order of life to the foolish society of materialistic men. Lord Śrī Caitanya Mahāprabhu and His subsequent followers exhibited expert dexterity in this connection. By following the same method, one can bring the materialistic men of this age of quarrel into order for peaceful life and transcendental realization.