There are three different kinds of devotees, namely kaniṣṭha-adhikārī, madhyama-adhikārī and uttama-adhikārī: the neophyte, the preacher and the mahā-bhāgavata, or the highly advanced devotee. The highly advanced devotee is one who knows the conclusion of the Vedas in full knowledge; thus he becomes a devotee. Indeed, not only is he convinced himself, but he can convince others on the strength of Vedic evidence. The advanced devotee can also see all other living entities as part and parcel of the Supreme Lord, without discrimination. The madhyama-adhikārī (preacher) is also well versed in the śāstras and can convince others also, but he discriminates between the favorable and the unfavorable. In other words, the madhyama-adhikārī does not care for the demoniac living entities, and the neophyte kaniṣṭha-adhikārī does not know much about śāstra but has full faith in the Supreme Personality of Godhead.
(Srimad Bhagavatam----4:22:16----purport).

For those who cannot properly appreciate the activities of authorized devotees, Deity worship is the only way for spiritual advancement. In the Caitanya-caritāmṛta (cc.3:7:11) it is clearly said, kṛṣṇa-śakti vinā nahe tāra pravartana: without being authorized by Kṛṣṇa, one cannot preach the holy name of the Lord throughout the entire world. Nevertheless, a devotee who does so is criticized by neophyte devotees, kaniṣṭha-adhikārīs, who are on the lower stages of devotional service. For them, Deity worship is strongly recommended.
(Srimad Bhagavatam----7:14:39----purport).

A devotee must carry out the order of the Supreme Personality of Godhead. Caitanya Mahāprabhu said, yāre dekha, tāre kaha 'kṛṣṇa'-upadeśa (cc.2:7:128). Every devotee, therefore, should spread Kṛṣṇa consciousness by preaching, asking whomever he meets to accept the order of the Supreme Personality of Godhead. The Lord says, sarva-dharmān parityajya mām ekaṁ śaraṇaṁ vraja: (B.G.18:66) "Abandon all varieties of religion and just surrender unto Me." This is the order of the Lord, who speaks as the supreme emperor. Everyone should be induced to accept this order, for this is victory (dig-vijaya). And it is the duty of the soldier, the devotee, to impress upon everyone this philosophy of life.
Of course, those who are kaniṣṭha-adhikārīs do not preach, but the Lord shows mercy to them also, as He did by staying personally in Ayodhyā to give audience to the people in general. One should not mistakenly think that the Lord asked His younger brothers to leave Ayodhyā because He especially favored the citizens. The Lord is merciful to everyone, and He knows how to show His favor to each individual person according to his capacity. One who abides by the order of the Lord is a pure devotee.
(Srimad Bhagavatam----9:11:25----purport).

There are three categories of Vaiṣṇavas: kaniṣṭha-adhikārīs, madhyama-adhikārīs and uttama-adhikārīs. The kaniṣṭha-adhikārī, or the devotee in the lowest stage of Vaiṣṇava life, has firm faith but is not familiar with the conclusions of the śāstras. The devotee in the second stage, the madhyama-adhikārī, is completely aware of the śāstric conclusion and has firm faith in his guru and the Lord. He, therefore, avoiding nondevotees, preaches to the innocent. However, the mahā-bhāgavata or uttama-adhikārī, the devotee in the highest stage of devotional life, does not see anyone as being against the Vaiṣṇava principles, for he regards everyone as a Vaiṣṇava but himself. This is the essence of Caitanya Mahāprabhu's instruction that one be more tolerant than a tree and think oneself lower than the straw in the street (tṛṇād api su-nīcena taror iva sahiṣṇunā). However, even if a devotee is in the uttama-bhāgavata status he must come down to the second status of life, madhyama-adhikārī, to be a preacher, for a preacher should not tolerate blasphemy against another Vaiṣṇava. Although akaniṣṭha-adhikārī also cannot tolerate such blasphemy, he is not competent to stop it by citing śāstric evidences. Therefore Tapana Miśra and Candraśekhara are understood to be kaniṣṭha-adhikārīs because they could not refute the arguments of the sannyāsīs in Benares. They appealed to Lord Caitanya Mahāprabhu to take action, for they felt that they could not tolerate such criticism although they also could not stop it.
(Sri Caitanya Caritamrta----1:7:51----purport).

Śrīla Bhaktivinoda Ṭhākura said that the position of a Vaiṣṇava can be tested by seeing how good a touchstone he is—that is, by seeing how many Vaiṣṇavas he has made during his life. A Vaiṣṇava should be a touchstone so that he can convert others to Vaiṣṇavism by his preaching, even though people may be fallen like the hunter. There are many so-called advanced devotees who sit in a secluded place for their personal benefit. They do not go out to preach and convert others into Vaiṣṇavas, and therefore they certainly cannot be called sparśa-maṇi, advanced devotees. Kaniṣṭha-adhikārī devotees cannot turn others into Vaiṣṇavas, but a madhyama-adhikārī Vaiṣṇava can do so by preaching. Śrī Caitanya Mahāprabhu advised His followers to increase the numbers of Vaiṣṇavas.
(Sri Caitanya Caritamrta----2:24:277----purport).