Srimad Bhagavatam Canto 07, Chapter 06, Text 27

SB 7.6.27

jñanam tad etad amalam duravapam aha
 narayano nara-sakhah kila naradaya
ekantinam bhagavatas tad akiñcananam
 padaravinda-rajasapluta-dehinam syat
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
Narayana, the Supreme Personality of Godhead, the well-wisher and friend of all living entities, formerly explained this transcendental knowledge to the great saint Narada. Such knowledge is extremely difficult to understand without the mercy of a saintly person like Narada, but everyone who has taken shelter of Narada’s disciplic succession can understand this confidential knowledge.
 
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
It is stated here that this confidential knowledge is extremely difficult to understand, yet it is very easy to understand if one takes shelter of a pure devotee. This confidential knowledge is also mentioned at the end of Bhagavad-gita, where the Lord says, sarva-dharman parityajya mam ekam saranam vraja: “Abandon all varieties of religion and just surrender unto Me.” This knowledge is an extremely confidential secret, but it can be understood if one approaches the Supreme Personality of Godhead through the bona fide agent, the spiritual master in the disciplic succession from Narada. Prahlada Maharaja wanted to impress upon the sons of the demons that although such knowledge can be understood only by a saintly person like Narada, they should not be disappointed, for if one takes shelter of Narada instead of material teachers, this knowledge is possible to understand. Understanding does not depend upon high parentage. The living entity is certainly pure on the spiritual platform, and therefore anyone who attains the spiritual platform by the grace of the spiritual master can also understand this confidential knowledge.
Srimad Bhagavatam Canto 07, Chapter 06, Text 26
Srimad Bhagavatam Canto 07, Chapter 06, Text 28