One who desires his ultimate self-interest should cultivate friendship with those persons who have accepted Kṛṣṇa as the Lord of their life. One should further develop an attitude of service toward all living beings. One should especially try to help those in the human form of life and, among them, especially those who accept the principles of religious behavior. Among religious persons, one should especially render service to the pure devotees of the Supreme Personality of Godhead.
(Srimad Bhagavatam----11:3:29----translation).

Every living entity is eternally a servant of Śrī Kṛṣṇa Caitanya; therefore the spiritual master cannot be other than a servant of Lord Caitanya. The spiritual master's eternal occupation is to expand the service of the Lord by training disciples in a service attitude. A spiritual master never poses as the Supreme Lord Himself; he is considered a representative of the Lord. The revealed scriptures prohibit one's pretending to be God, but a bona fide spiritual master is a most faithful and confidential servant of the Lord and therefore deserves as much respect as Kṛṣṇa.
(Sri Caitanya Caritamrta----1:1:44----purport).

The Lord's mercy descends to a devotee like Brahmā and, through Brahmā, to Nārada, from Nārada to Vyāsa, from Vyāsadeva to Śukadeva and so on in the bona fide chain of disciplic succession. We cannot discover the mysteries of the Lord by our mundane endeavors; they are only revealed, by His grace, to the proper devotees. These mysteries are gradually disclosed to the various grades of devotees in proportion to the gradual development of their service attitude. In other words, impersonalists who depend upon the strength of their poor fund of knowledge and morbid speculative habits, without submission and service in the forms of hearing, chanting and the others mentioned above, cannot penetrate to the mysterious region of transcendence where the Supreme Truth is a transcendental person, free from all tinges of the material elements.
(Sri Caitanya Caritamrta----1:1:52----purport).

"The great scripture Śrīmad-Bhāgavatam, compiled by Mahā-muni Vyāsadeva from four original verses, describes the most elevated and kindhearted devotees and completely rejects the cheating ways of materially motivated religiosity. It propounds the highest principle of eternal religion, which can factually mitigate the threefold miseries of a living being and award the highest benediction of full prosperity and knowledge. Those willing to hear the message of this scripture in a submissive attitude of service can at once capture the Supreme Lord in their hearts. Therefore there is no need for any scripture other than Śrīmad-Bhāgavatam."
(Srimad Bhagavatam----1:1:91----translation).

A living entity situated in the status of pure goodness can understand the form, qualities and other features of the Supreme Personality of Godhead. Kṛṣṇa consciousness begins on the platform of pure goodness. Although there is a faint realization of Kṛṣṇa at first, Kṛṣṇa is actually realized as Vāsudeva, the absolute proprietor of omnipotence or the prime predominating Deity of all potencies. When the living entity is situated in viśuddha-sattva, transcendental to the three material modes of nature, he can perceive the form, quality and other features of the Supreme Personality of Godhead through his service attitude. The status of pure goodness is the platform of understanding, for the Supreme Lord is always in spiritual existence.
(Sri Caitanya Caritamrta----1:4:65----purport).

The conditioned state is caused by misuse of the individual independence of the spiritual platform, for this separates the living entity from the association of the spiritual energy. But when the living entity is enlightened by the grace of the Supreme Lord or His pure devotee and becomes inclined to revive his original state of loving service, he is on the most auspicious platform of eternal bliss and knowledge. The marginal jīva, or living entity, misuses his independence and becomes averse to the eternal service attitude when he independently thinks he is not energy but the energetic. This misconception of his own existence leads him to the attitude of lording it over material nature.
(Sri Caitanya Caritamrta----1:5:66----purport).

There are two kinds of devotional service: the way of pāñcarātrika regulative principles and the way of bhāgavata transcendental loving service. The love of Godhead of those engaged in pāñcarātrika regulative principles depends more or less on the opulent and reverential platform, but the worship of Rādhā and Kṛṣṇa is purely on the platform of transcendental love. Even persons who play as the superiors of Kṛṣṇa also take the chance to offer transcendental loving service to the Lord. The service attitude of the devotees who play the parts of superiors of the Lord is very difficult to understand, but it can be very plainly understood in connection with the superexcellence of their particular service to Lord Kṛṣṇa.
(Sri Caitanya Caritamrta----1:6:53----purport).

Kṛṣṇadāsa Kavirāja Gosvāmī explains, kṛṣṇa-śakti vinā nahe tāra pravartana: unless one receives special power of attorney from the Supreme Personality of Godhead, he cannot preach the glories of the Hare Kṛṣṇa mahā-mantra. As devotees propagate the Hare Kṛṣṇa mahā-mantra, the general population of the entire world gets the opportunity to understand the glories of the holy name. While chanting and dancing or hearing the holy name of the Lord, one automatically remembers the Supreme Personality of Godhead, and because there is no difference between the holy name and Kṛṣṇa, the chanter is immediately linked with Kṛṣṇa. Thus connected, a devotee develops his original attitude of service to the Lord. In this attitude of constantly serving Kṛṣṇa, which is called bhāva, he always thinks of Kṛṣṇa in many different ways. One who has attained this bhāva stage is no longer under the clutches of the illusory energy. When other spiritual ingredients, such as trembling, perspiration and tears, are added to this bhāva stage, the devotee gradually attains love of Kṛṣṇa.
(Sri Caitanya Caritamrta----1:7:83----purport).