bhāgavata-ādi śāstrera yata gūḍha marma
tāṅre-unto him (Sanātana Gosvāmī); śikhāilā-the Lord taught him; saba-all; vaiṣṇavera-of the devotees; dharma-regular activities; bhāgavata-Śrīmad-Bhāgavatam; ādi-beginning with; śāstrera-of the revealed scriptures; yata-all; gūḍha-confidential; marma-purpose.
On the basis of scriptures like Śrīmad-Bhāgavatam, which reveal these confidential directions, Śrī Caitanya Mahāprabhu instructed Sanātana Gosvāmī regarding all the regular activities of a devotee.
"The real import of the scriptures is revealed to one who has unflinching faith in both the Supreme Personality of Godhead and the spiritual master." Śrīla Narottama dāsa Ṭhākura advises, sādhu-śāstra-guru-vākya, hṛdaye kariyā aikya. The meaning of this instruction is that one must consider the instructions of the sādhu, the revealed scriptures and the spiritual master in order to understand the real purpose of spiritual life. Neither a sādhu (saintly person or Vaiṣṇava) nor a bona fide spiritual master says anything that is beyond the scope of the sanction of the revealed scriptures. Thus the statements of the revealed scriptures correspond to those of the bona fide spiritual master and saintly persons. One must therefore act with reference to these three important sources of understanding.