In Bhagavad-gītā, Thirteenth Chapter, it is clearly stated that one should execute devotional service and advance on the path of spiritual knowledge by accepting the ācārya. Ācāryopāsanam: one should worship an ācārya, a spiritual master who knows things as they are. The spiritual master must be in the disciplic succession from Kṛṣṇa. The predecessors of the spiritual master are his spiritual master, his grand spiritual master, his great-grand spiritual master and so on, who form the disciplic succession of ācāryas.
It is recommended herewith that all the ācāryas be given the highest respect. It is stated, guruṣu nara-matiḥ. Guruṣu means "unto the ācāryas," and nara-matiḥ means "thinking like a common man." To think of the Vaiṣṇavas, the devotees, as belonging to a particular caste or community, to think of the ācāryas as ordinary men or to think of the Deity in the temple as being made of stone, wood or metal, is condemned. Niyamena: one should offer the greatest respect to the ācāryas according to the standard regulations. A devotee should also be compassionate to the poor. This does not refer to those who are poverty-stricken materially. According to devotional vision, a man is poor if he is not in Kṛṣṇa consciousness. A man may be very rich materially, but if he is not Kṛṣṇa conscious, he is considered poor. On the other hand, many ācāryas, such as Rūpa Gosvāmī and Sanātana Gosvāmī, used to live beneath trees every night. Superficially it appeared that they were poverty-stricken, but from their writings we can understand that in spiritual life they were the richest personalities.
A devotee shows compassion to those poor souls who are wanting in spiritual knowledge by enlightening them in order to elevate them to Kṛṣṇa consciousness. That is one of the duties of a devotee. He should also make friendship with persons who are on an equal level with himself or who have the same understanding that he does. For a devotee, there is no point in making friendships with ordinary persons; he should make friendship with other devotees so that by discussing among themselves, they may elevate one another on the path of spiritual understanding. This is called iṣṭa-goṣṭhī.
In Bhagavad-gītā there is reference to bodhayantaḥ parasparam, "discussing among themselves." Generally pure devotees utilize their valuable time in chanting and discussing various activities of Lord Kṛṣṇa or Lord Caitanya amongst themselves. There are innumerable books, such as the purāṇas, Mahābhārata, Bhāgavatam, Bhagavad-gītā and Upaniṣads, which contain countless subjects for discussion among two devotees or more. Friendship should be cemented between persons with mutual interests and understanding. Such persons are said to be sva jāti, "of the same caste." The devotee should avoid a person whose character is not fixed in the standard understanding; even though he may be a Vaiṣṇava, or a devotee of Kṛṣṇa, if his character is not correctly representative, then he should be avoided. One should steadily control the senses and the mind and strictly follow the rules and regulations, and he should make friendship with persons of the same standard.