SB 11.11.48

prāyeṇa bhakti-yogena
 sat-saṅgena vinoddhava
nopāyo vidyate samyak
 prāyaṇaṁ hi satām aham
Synonyms: 
prāyeṇa — for all practical purposes; bhakti-yogena — devotional service unto Me; sat-saṅgena — which is made possible by association with My devotees; vinā — without; uddhava — O Uddhava; na — not; upāyaḥ — any means; vidyate — there is; samyak — that actually works; prāyaṇam — the true path of life or actual shelter; hi — because; satām — of liberated souls; aham — I.
Translation: 
My dear Uddhava, I am personally the ultimate shelter and way of life for saintly liberated persons, and thus if one does not engage in My loving devotional service, which is made possible by associating with My devotees, then for all practical purposes, one possesses no effective means for escaping from material existence.
Purport: 

Lord Kṛṣṇa has described to Uddhava the characteristics of jñāna-yoga and bhakti-yoga, both of which are considered to be spiritual processes. Now, however, Lord Kṛṣṇa clearly indicates that bhakti-yoga is the only real means to totally free oneself from material existence, and that bhakti-yoga is not possible without sat-saṅga, or association with other Vaiṣṇavas. On the path of bhakti-miśra jñāna, or speculation on the Absolute Truth mixed with devotion, one is still affected by the three modes of material nature. The pure soul, liberated from all material qualities, has no tendency or desire to engage in philosophical speculation, severe austerities or impersonal meditation. The pure soul simply loves Kṛṣṇa and wants to serve Him constantly. Jīvera ‘svarūpa’ hayakṛṣṇera ‘nitya-dāsa.’ Pure devotional service to the Lord is called kevala-bhakti, whereas devotional service mixed with speculative propensities is called guṇa-bhūta-bhakti, or devotional service polluted by the material modes of nature. One who is actually intelligent does not make a show of philosophical wizardry but rather discerns the superiority of pure love of Godhead and takes to the path of kevala-bhakti. One who emphasizes so-called intellectual achievements is actually less intelligent, because such a person is more attracted to intelligence than to the pure soul, which is superior. It should be understood, however, that pure devotional service is not nonphilosophical or anti-intellectual. The Absolute Truth is far more extensive than partial truth. Therefore, one who is in full knowledge of Lord Kṛṣṇa has the greatest facility to engage in philosophical analysis, since a pure devotee is working with the entire range of conceptual categories. Those who do not know Lord Kṛṣṇa are attracted to the impersonal Brahman or the localized Paramātmā, but they are not aware of the ultimate category of understanding called Bhagavān, or the Supreme Personality of Godhead. Lacking knowledge of Bhagavān, such imperfect philosophers certainly do not understand the expansion, interaction and withdrawal of the Lord’s innumerable potencies and thus cannot fully analyze them. By faithfully accepting everything Lord Kṛṣṇa speaks as the absolute truth, one comes to the mature platform of philosophy and achieves perfect knowledge.

In addition to philosophical or intellectual understanding, pure devotional service also awards all other benefits in life, both material and spiritual; therefore one who for any purpose whatsoever accepts a process other than devotional service has unfortunately misunderstood the nature of pure devotional service to Lord Kṛṣṇa. It is emphasized here that one must cultivate devotional service in the association of other devotees. On the other hand, the jñāna-yoga process is cultivated alone, because it is difficult for even two mental speculators to be in the same place without their association degenerating into constant quarrel. Other processes of self-realization are compared to the nipples on a goat’s neck. They look just like breast nipples, but they will not give any milk whatsoever. In this regard Śrīla Viśvanātha Cakravartī Ṭhākura has quoted the following verses, spoken by Śrī Uddhava, Śukadeva Gosvāmī and Nārada Muni respectively.

tāpa-trayeṇābhihitasya ghore
 santapyamānasya bhavādhvanīha
paśyāmi nānyac charaṇaṁ tavāṅghri-
 dvandvātapatrād amṛtābhivarṣāt

“My dear Lord, for one who is being cruelly burned in the blazing fire of material miseries, having fallen into the network of material existence, I do not see any other possible shelter besides Your two lotus feet, which are a shower of nectar extinguishing the fire of suffering.” (Bhāg. 11.19.9)

saṁsāra-sindhum ati-dustaram uttitīrṣor
 nānyaḥ plavo bhagavataḥ puruṣottamasya
līlā-kathā-rasa-niṣevaṇam antareṇa
 puṁso bhaved vividha-duḥkha-davārditasya

“Material existence is like an ocean that is extremely difficult to cross. The conditioned souls have fallen into this ocean, which is not cool but rather burns them with the fire of misery. For one who has fallen into this sea and desires to get out, there is no other rescue boat except the constant relishing within oneself of the pastime narrations of the Supreme Personality of Godhead.” (Bhāg. 12.4.40)

kiṁ vā yogena sāṅkhyena
 nyāsa-svādhyāyayor api
kiṁ vā śreyobhir anyaiś ca
 na yatrātma-prado hariḥ

“What is the use of the yoga system, philosophical speculation, mere renunciation of the world, or Vedic studies? In fact, what is the use of any so-called auspicious process without Lord Kṛṣṇa, who is the source of our very existence?” (Bhāg. 4.31.12)

If, as stated in this verse, it is generally (prāyeṇa) impossible to escape material bondage without devotional service in the association of devotees, one can simply imagine the probabilities of liberation in Kali-yuga without the Kṛṣṇa consciousness movement. The chances are certainly zero. One may concoct a type of liberation on the mental platform, or one may live in a so-called spiritual society of mutual flattery, but if one actually wants to go back home, back to Godhead, and see with spiritual eyes the beautiful kingdom of God called Kṛṣṇaloka, one must take to Lord Caitanya’s movement and worship Lord Kṛṣṇa in the association of the bhakta-gaṇa, the devotees of the Lord.