Srimad-Bhagavatam 2.8.4-5

srnvatah sraddhaya nityam grnatas ca sva-cestitam kalena natidirghena
bhagavan visate hrdi

TRANSLATION: Persons who hear Srimad-Bhagavatam regularly and are
always taking the matter very seriously will have the Personality of
Godhead Sri Krsna manifested in their hearts within a short time.

pravistah karna-randhrenasvanam bhava-saroruhamdhunoti samalam
Krsnahsalilasya yatha sarat

TRANSLATION: The sound incarnation of Lord Krsna, the Supreme Soul
[i.e. Srimad-Bhagavatam], enters into the heart of a self-realized
devotee, sits on the lotus flower of his loving relationship, and thus
cleanses the dust of material association, such as lust, anger and
hankering. Thus it acts like autumnal rains upon pools of muddy water.


PURPORT
The comparison to the autumnal rain that falls on muddy reservoirs of
water is very appropriate. During the rainy season, all the waters of
the rivers become muddy, but in the month of July-August, the autumn
season, when there is a slight rainfall, the muddy waters of the
rivers all over the world become at once clear. By addition of some
chemical, a small reservoir of water like that of a metropolitan
waterworks tank can be cleared, but by such a tiny effort it is not
possible to clear up all the reservoirs of water like the rivers. A
powerful pure devotee of the Lord, however, can deliver not only his
personal self but also many others in his association.


By sincere efforts to hear Srimad-Bhagavatam one realizes his
constitutional relationship with the Lord in the transcendental humor
of servitude, friendship, paternal affection or conjugal love, and by
such self-realization one becomes situated at once in the
transcendental loving service of the Lord.


Not only were all the pure devotees like Narada self-realized souls,
but they were engaged in preaching work automatically by spiritual
impetus, and thus they delivered many poor souls entangled in the
material modes. They became so powerful because they sincerely
followed the Bhagavatam principles by regular hearing and worshiping.
By such actions the accumulated material lusts, etc., become cleansed
by the personal endeavor of the Lord within the heart. The Lord is
always within the heart of the living being, but He becomes manifested
by one's devotional service