Vedic Knowledge is manifested in heart of a Devotee

When all the students thus resolved, criticizing Śrī Caitanya Mahāprabhu, their intelligence was spoiled. Thus although they were learned scholars, because of this offense the essence of knowledge was not manifested in them.

In the Bhagavad-gītā it is said, māyayāpahṛta-jñānā āsuraṁ bhāvam āśritāḥ: when one becomes inimical to the Supreme Personality of Godhead, adopting an atheistic attitude (āsuraṁ bhāvam), even if one is a learned scholar the essence of knowledge does not become manifested in him; in other words, the essence of his knowledge is stolen by the illusory energy of the Lord. In this connection Śrī Bhaktisiddhānta Sarasvatī Ṭhākura quotes a mantra from the Śvetāśvatara Upaniṣad (6.23):

yasya deve parā bhaktir yathā deve tathā gurau

tasyaite kathitā hy arthāḥ prakāśante mahātmanaḥ

(ŚU 6.23)

The purport of this verse is that one who is unflinchingly devoted to the Supreme Personality of Godhead, Viṣṇu, and similarly devoted to the spiritual master, with no ulterior motive, becomes a master of all knowledge. In the heart of such a devotee, the real essence of the Vedic knowledge becomes manifested. This essence is nothing but surrender unto the Supreme Personality of Godhead (vedaiś ca sarvair aham eva vedyaḥ ((BG 15.15)). Only unto one who fully surrenders to the spiritual master and the Supreme Lord does the essence of Vedic knowledge become manifested, not to anyone else.

Caitanya Caritamrta Adi 17.257