"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... 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."
(Srila Prabhupada Lecture, Vrindavan, October 4, 1976)