SB 1.2.13 Hear submissively to make advancement

Important points from the purport to the verse:

tac chraddadhānā munayo jñāna-vairāgya-yuktayā

paśyanty ātmani cātmānaḿ bhaktyā śruta-gṛhītayā

The seriously inquisitive student or sage, well equipped with knowledge and detachment, realizes that Absolute Truth by rendering devotional service in terms of what he has heard from the Vedānta-śruti.

Points from Srila Prabhupada's purport

Book Bhagavat and person Bhagavat

1. A third class devotee is one who has knowledge - engages in so called devotional service is not detached from material association
2.  Therefore he has to receive instructions from authoritative sources of Bhagavata - the personality of a devotee and the Book Bhagavatam
3. A sincere devotee must, therefore, be prepared to hear the Vedic literature like the Upaniṣads, Vedānta and other literatures left by the previous authorities or Gosvāmīs, for the benefit of his progress. Without hearing such literatures, one cannot make actual progress. And without hearing and following the instructions, the show of devotional service becomes worthless and therefore a sort of disturbance in the path of devotional service. Unless, therefore, devotional service is established on the principles of śruti, smṛti, purāṇa or pañcarātra authorities, the make-show of devotional service should at once be rejected. An unauthorized devotee should never be recognized as a pure devotee. By assimilation of such messages from the Vedic literatures, one can see the all-pervading localized aspect of the Personality of Godhead within his own self constantly. This is called samādhi.