"Sanātana Gosvāmī has, in his Hari-bhakti-vilāsa, has very strongly recommended that, 'Don't hear anything from, about Kṛṣṇa, from the Māyāvādīs (impersonalists) or the avaiṣṇavas' (nondevotees). Those who are follower, those who are advanced in Kṛṣṇa consciousness, they can protest. They can immediately chastise the rascal, 'What you are nonsense speaking?' But a kaniṣṭha-adhikārī (neophyte), he cannot challenge, therefore it is forbidden for them. Not to hear, kaniṣṭha-adhikārī. For an advanced devotee, this Māyāvādī cannot do anything, but those who are neophyte, they become sometimes victim. Therefore, it is better to forbid them, not to hear. So Sanātana Gosvāmī has said, as Kṛṣṇa has said, satāṁ prasaṅgān mama vīrya-saṁvido bhavanti hṛt-karṇa-rasāyanāḥ kathāḥ (SB 3.25.25). In the association of pure devotees, kṛṣṇa-kathāḥ becomes very relishable. Hṛt-karṇa-rasāyanāḥ. It is relishable, it is very pleasing to the ear, and to the heart. Hṛt means heart, and karṇa means this aural reception. Both ways pleasing, bhavanti hṛt-karṇa. Taj-joṣaṇād, if one little tries whatever he has heard, then śraddhā ratir bhaktir anukramiṣyati. Śraddhā, the real beginning is śraddhā (firm faith).
ādau śraddhā tataḥ sādhu-
saṅga tato bhajana-kriyā
tato anartha-nivṛttiḥ syāt
tato niṣṭhā tato ruci
athāsaktis tato bhāvas
sādhakānām ayaṁ premṇaḥ
prādurbhāve bhavet kramaḥ
(CC Madhya 23.14-15)
These are the different states. So śraddhā. So, by hearing from pure devotees, satāṁ prasaṅgān mama vīrya-saṁvido bhavanti hṛt-karṇa-rasāyanāḥ kathāḥ (SB 3.25.25). It will be very pleasing to the heart, to the ear, taj-joṣaṇād āśu apavarga-vartmani. Śraddhā, beginning is śraddhā, śraddhā ratir bhaktir anukramiṣyati. Therefore this Kṛṣṇa consciousness movement, the Association is opening different branches to give people the chance of hearing about Kṛṣṇa in the association of pure devotees. That is required. Read, hear about Bhagavad-gītā from the pure devotees, not from the rascals. Then you'll never get any benefit.
Sanātana Gosvāmī forbids... nasam, śravaṇaṁ na kartavyam, never hear from these rascals. 'Why? Kṛṣṇa-kathāḥ is very good. Never mind he's a rascal, what is the fault of kṛṣṇa-kathāḥ?' He's giving this example: śravaṇaṁ na kartavyaṁ sarpocchiṣṭaṁ payaḥ yathā, milk is very good, everyone knows, but when it is touched by the lip of a serpent, immediately it becomes poison. If you take that milk, then you'll die. So kṛṣṇa-kathāḥ is very good, but when it is touched by the lip of the Māyāvādī, nondevotee, it becomes poisonous. It becomes poisonous. Poisonous in this sense. It will push you far away from kṛṣṇa-bhakti. That is the loss, greatest loss of life.
This life is meant for developing Kṛṣṇa consciousness, to become devotee of Kṛṣṇa. Bhagavad-gītā is left by Kṛṣṇa to make all people after Him, to become devotees. Man-manā bhava mad-bhakto mad-yājī māṁ namaskuru (BG 18.65). The instruction is there, but these rascals will spoil. They will never allow you to become a devotee. These rascals are so dangerous. They are going against the will of Kṛṣṇa. So one must be very careful to save himself from the poisonous effect of these rascals."
(Srila Prabhupada Lecture, Bombay, January 8, 1973)