(His Divine Grace A.C. Bhaktivedanta Swami Prabhupada—click to enlarge)
Prabhupāda: Real success is how one is faithful to his guru. That is real success. Yasya deve parā bhaktir yathā deve tathā gurau. It is not by education or grammatical knowledge you can learn anything. No. It is by the grace of the Supreme Personality of Godhead. And that grace comes down through the grace of guru. That grace also does not come directly. We should not be neglecting this point.
yasya deve parā bhaktir
yathā deve tathā gurau
tasyaite kathitā hy arthāḥ
Things become revealed by devotion, not by so-called education. No. Ciraṁ vicinvan. Na cānya eko 'pi ciraṁ vicinvan, prasāda-leśānugṛhīta eva hi (SB 10.14.29). By little prasāda, satisfaction... In many places these things are stated. Yat kāruṇya-katākṣa-vaibhavavatāṁ gauram eva stumaḥ. Kāruṇya-katākṣa. Not complete kāruṇya, but katākṣa, simply little glancing, he becomes so great, kaivalyaṁ narakāyate tridaśa-pūr ākāśa...
Therefore Viśvanātha Cakravartī Ṭhākura says, yasya prasādād bhagavat-prasādaḥ... Not that bhagavat-prasāda is achieved by education and grammar. No. Yasya prasādād bhagavat-prasādaḥ... By the mercy of guru one can achieve. That is just like a common word, "If you love me, love my dog." So you cannot approach Kṛṣṇa without loving His dog, His servant. Satāṁ prasaṅgāt. A person who is trying to distribute the message of Kṛṣṇa, he is very, very dear dog of Kṛṣṇa. Na ca tasmān manuṣyeṣu kaścin me priya-kṛttamaḥ (BG 18.69). He is very... It doesn't matter how far he is advanced in education, how far he has learned grammar. These are not the things. The things is how far he is working to carry out the mission of Kṛṣṇa. Then one has to receive Kṛṣṇa's mercy through the bona fide servant. Kṛṣṇa cannot be bluffed by so-called education and grammar. Kṛṣṇa is not so...
Bhaktyā mām abhijānāti (BG 18.55). He never says "By grammar or by education one can understand." Never says. Bhaktyā mām abhijānāti yāvān yaś cāsmi tattvataḥ. We should be educated, we should be very careful, but real thing is bhakti. Anyābhi... Bhajate mām ananya-bhāk, sādhur eva sa mantavyaḥ (BG 9.30). Api cet su-durācāraḥ. Many places it is said. Tad-vāg-visargo janatāgha-viplavo yasmin prati-ślokam abaddhavaty api (SB 1.5.11). Even a bhakta writes something which is not very grammatically, rhetorically correct... Tad-vāg-visargo janatāgha-viplavaḥ, nāmāny anantasya yaśo 'ṅkitāni yat. But because he has tried to broadcast the glories of the Lord, even not in perfect language, that is his qualification.
yasmin prati-ślokam abaddhavaty api
nāmāny anantasya yaśo 'ṅkitāni yat
śṛṇvanti gāyanti gṛṇanti sādhavaḥ
The sādhus, they are not interested about rhetorical or grammatical adjustment. The sādhu wants to see who has spoken. If he's a Vaiṣṇava, then his word will be accepted. Caitanya Mahāprabhu strictly prohibits that is one is not a Vaiṣṇava, don't hear from him. Avaiṣṇava-mukhodgīrṇaṁ pūtaṁ hari-kathāmṛtam, śravaṇaṁ naiva kartavyam. "But he's such a learned man," or "He's writes so nicely, correctly." But because he's not Vaiṣṇava, one should not hear from him. "Why? It is so nicely written." No. Sarpocchiṣṭaṁ yathā payaḥ. Milk is very good food, everyone knows. But as soon as it is touched by the lips of a serpent, it is poison immediately. Therefore it is forbidden. And one who has no knowledge how to respect guru, how he can become Vaiṣṇava? Chāḍiyā vaiṣṇava-sevā nistāra pāyeche kebā, Narottama dāsa Ṭhākura says. If you don't become a faithful servant of Vaiṣṇava, there is no possibility of your liberation. Chāḍiyā vaiṣṇava-sevā nistāra pāyecha kebā. Tāṅdera caraṇa-sevi-bhakta-sane vāsa, janame janame haya ei abhilāṣa. This is Narottama dāsa Ṭhākura's...
Our determination should be to serve the previous guru and ācārya. Evaṁ paramparā-prāptam (BG 4.2). That is our determination. Tāṅdera caraṇa-sevi. Our service... Not directly Kṛṣṇa. Because to serve Vaiṣṇava is more than serving Kṛṣṇa directly. Mad-bhakta-pūjābhyadhikā (SB 11.19.21). Kṛṣṇa likes that. He doesn't accept anyone's service directly. That is a gross mistake. Therefore Narottama dāsa Ṭhākura is teaching us... (break) ...trying to become one with Kṛṣṇa or one with the gopīs. These are all Māyāvāda philosophy. Tāṅdera caraṇa-sevi. You have to serve the servant of Kṛṣṇa, tad bhṛtya dāsa-dāsa-dāsānudāsaḥ (CC Madhya 13.80). That is the way. Not directly.
(Srila Prabhupada Lecture, Vrindavan, October 4, 1976)