Lord Caitanya came to earth simply to preach kṛṣṇa-bhakti, love of Kṛṣṇa.
(SRI CAITANYA CARITAMRTA------INTRODUCTION).

Lord Caitanya accepted sannyāsa, leaving aside His householder life, to preach His mission.
(SRI CAITANYA CARITAMRTA-------1:3:49------PURPORT).

To preach kṛṣṇa-kathā all over the world, as recommended by Lord Caitanya, is the greatest missionary activity, and all sensible men and women of the world may join in this great movement started by Lord Caitanya.
(SRIMAD BHAGAVATAM------3:5:11--------PURPORT).

Śrī Kṛṣṇa Caitanya, who was outwardly very fair, with a complexion like molten gold, simultaneously manifested His eternal associates, opulences, expansions and incarnations. He preached the process of chanting Hare Kṛṣṇa, and those who are under His lotus feet are glorious.
(SRI CAITANYA CARITAMRTA-------1:3:81------PURPORT).

Unless one is a first-class devotee, he cannot be a preacher. A preacher is generally a topmost devotee, but in order to meet the general populace, he has to come to distinguish between devotees and nondevotees. Otherwise, an advanced devotee makes no such distinctions. Indeed, he always sees that everyone is engaged in the service of the Lord. When one engages in preaching work, he must distinguish between people and understand that some people are not engaged in the devotional service of the Lord. The preacher then has to take compassion upon such innocent people who do not know how to worship the Lord.
(SRI CAITANYA CARITAMRTA-------2:8:44------PURPORT).

A sannyāsī is supposed to beg from door to door. He does not beg simply because he is hungry. His real purpose is to enlighten the occupant of every house bypreaching Kṛṣṇa consciousness. A sannyāsī does not abandon his superior position and become a beggar just for the sake of begging. Similarly, a person in householder life may be very important, but he may also voluntarily take to the mendicant way of life. Rūpa Gosvāmī and Sanātana Gosvāmī were ministers, but they voluntarily accepted the mendicant's life in order to humbly preach Śrī Caitanya Mahāprabhu's message.
(SRI CAITANYA CARITAMRTA-------2:8:39------PURPORT).

An ācārya who comes for the service of the Lord cannot be expected to conform to a stereotype, for he must find the ways and means by which Kṛṣṇa consciousness may be spread. Sometimes jealous persons criticize the Kṛṣṇa consciousness movement because it engages equally both boys and girls in distributing love of Godhead. Not knowing that boys and girls in countries like Europe and America mix very freely, these fools and rascals criticize the boys and girls in Kṛṣṇa consciousness for intermingling. But these rascals should consider that one cannot suddenly change a community's social customs. However, since both the boys and the girls are being trained to become preachers, those girls are not ordinary girls but are as good as their brothers who are preaching Kṛṣṇa consciousness. Therefore, to engage both boys and girls in fully transcendental activities is a policy intended to spread the Kṛṣṇa consciousness movement.
(SRI CAITANYA CARITAMRTA-------1:7:31-32------PURPORT).

This is a manifestation of real love for Kṛṣṇa and Lord Caitanya Mahāprabhu. 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.
(SRI CAITANYA CARITAMRTA-------1:7:51------PURPORT).

A Vaiṣṇava sannyāsī or a Vaiṣṇava in the second stage of advancement in spiritual knowledge can understand four principles—namely, the Supreme Personality of Godhead, the devotees, the innocent and the jealous—and he behaves differently with each. He tries to increase his love for Godhead, make friendship with devotees and preach Kṛṣṇa consciousness among the innocent, but he avoids the jealous who are envious of the Kṛṣṇa consciousness movement. Lord Caitanya Mahāprabhu Himself exemplified such behavior, and this is why Prakāśānanda Sarasvatī inquired why He did not associate or even talk with them. Caitanya Mahāprabhu confirmed by example that a preacher of the Kṛṣṇa consciousness movement generally should not waste his time talking with Māyāvādī sannyāsīs, but when there are arguments on the basis of śāstra, a Vaiṣṇava must come forward to talk and defeat them in philosophy.
(SRI CAITANYA CARITAMRTA-------1:7:67------PURPORT).

Many fools, not knowing the transcendental nature of the Hare Kṛṣṇa mahā-mantra, sometimes impede our loudly chanting this mantra, yet one who is actually advanced in the fulfillment of chanting the Hare Kṛṣṇa mahā-mantra induces others to chant also. 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.
(SRI CAITANYA CARITAMRTA-------1:7:83------PURPORT).

One should not attempt to imitate such exalted devotees. Rather, everyone should endeavor to preach the cult of Śrī Caitanya Mahāprabhu in all parts of the world and thus become successful in spiritual life. One who is not very expert in preaching may chant in a secluded place, avoiding bad association, but for one who is actually advanced,preaching and meeting people who are not engaged in devotional service are not disadvantages. A devotee gives the nondevotees his association but is not affected by their misbehavior. Thus by the activities of a pure devotee even those who are bereft of love of Godhead get a chance to become devotees of the Lord one day.
(SRI CAITANYA CARITAMRTA-------1:7:92------PURPORT).

Lord Caitanya Mahāprabhu has already sanctified the entire universe by His presence five hundred years ago, and therefore anyone who attempts to serve Śrī Caitanya Mahāprabhu sincerely by following in His footsteps and following the instructions of the ācāryas will successfully be able to preach the holy names of the Hare Kṛṣṇa mahā-mantra all over the universe. There are some foolish critics who say that Europeans and Americans cannot be offered sannyāsa, but here we find that Śrī Caitanya Mahāprabhu wanted to preachthe saṅkīrtana movement all over the universe. For preaching work, sannyāsīs are essential. These critics think that only Indians or Hindus should be offered sannyāsa to preach, but their knowledge is practically nil. Without sannyāsīs, the preaching work will be impeded. Therefore, under the instruction of Lord Caitanya and with the blessings of His associates, there should be no discrimination in this matter, but people in all parts of the world should be trained to preach and given sannyāsa so that the cult of Śrī Caitanya Mahāprabhu's saṅkīrtana movement will expand boundlessly. We do not care about the criticism of fools. We shall go on with our work and simply depend on the blessings of Lord Caitanya Mahāprabhu and His associates, the Pañca-tattva.
(SRI CAITANYA CARITAMRTA-------1:7:163------PURPORT).

Śrī Caitanya Mahāprabhu wanted to preach the saṅkīrtana movement of love of Kṛṣṇa throughout the entire world, and therefore during His presence He inspired the saṅkīrtana movement. Specifically, He sent Rūpa Gosvāmī and Sanātana Gosvāmī to Vṛndāvana and Nityānanda to Bengal and personally went to South India. In this way He kindly left the task of preaching His cult in the rest of the world to the International Society for Krishna Consciousness. The members of this Society must always remember that if they stick to the regulative principles and preach sincerely according to the instructions of the ācāryas, surely they will have the profound blessings of Lord Caitanya Mahāprabhu, and their preaching work will be successful everywhere throughout the world.
(SRI CAITANYA CARITAMRTA-------1:7:171------PURPORT).

It is an offense to preach the glories of the holy name among persons who have no intelligence or no faith in the subject matter. Such people should be given the chance to hear the chanting of the Hare Kṛṣṇa mantra, but in the beginning they should not be instructed about the glories or the spiritual significance of the holy name. By constant hearing of the holy name, their hearts will be purified, and then they will be able to understand the transcendental position of the holy name.
(SRI CAITANYA CARITAMRTA-------1:8:24------PURPORT).

The citizens of the state must give in charity up to fifty percent of their income for the purpose of creating a spiritual atmosphere in the state or in human society, both individually and collectively. They should preach the principles of Bhāgavatam by (a) karma-yoga, or doing everything for the satisfaction of the Lord, (b) regular hearing of the Śrīmad-Bhāgavatam from authorized persons or realized souls, (c) chanting of the glories of the Lord congregationally at home or at places of worship, (d) rendering all kinds of service to bhāgavatas engaged in preaching Śrīmad-Bhāgavatam and (e) residing in a place where the atmosphere is saturated with God consciousness. If the state is regulated by the above process, naturally there will be God consciousness everywhere.
(SRIMAD BHAGAVATAM------1:17:38--------PURPORT).

To blaspheme the great saintly persons who are engaged in preaching the glories of the Hare Kṛṣṇa mahā-mantra is the worst offense at the lotus feet of the holy name. One should not criticize a preacher of the glories of the Hare Kṛṣṇa mahā-mantra. If one does so, he is an offender. The Nāma-prabhu, who is identical with Kṛṣṇa, will never tolerate such blasphemous activities, even from one who passes as a great devotee.
(SRI CAITANYA CARITAMRTA-------1:8:24------PURPORT).

Sūta Gosvāmī learned the science of Kṛṣṇa from great ṛṣis and authorities like Śukadeva and Vyāsadeva and he was so qualified that even the sages of Naimiṣāraṇya eagerly wanted to hear from him the science of Kṛṣṇa in the form of Śrīmad-Bhāgavatam. So he had the double association of great souls by hearing and preaching. Transcendental science, or the science of Kṛṣṇa, has to be learned from the authorities, and when one preaches the science, he becomes still more qualified. So Sūta Gosvāmī had both the advantages, and thus undoubtedly he was completely freed from all disqualifications of low birth and mental agonies. This verse definitely proves that Śrīla Śukadeva Gosvāmī did not refuse to teach Sūta Gosvāmī about the transcendental science nor did the sages of Naimiṣāraṇya refuse to hear lessons from him because of his inferior birth. This means that thousands of years ago there was no bar to learning or preaching the transcendental science because of inferior birth. The rigidity of the so-called caste system in Hindu society became prominent within only one hundred years or so when the number of dvija-bandhus, or disqualified men in the families of higher castes, increased. Lord Śrī Caitanya revived the original Vedic system, and He elevated Ṭhākura Haridāsa to the position of nāmācārya, or the authority in preaching the glories of the holy name of the Lord, although His Holiness Śrīla Haridāsa Ṭhākura was pleased to appear in a family of Mohammedans.
(SRIMAD BHAGAVATAM------1:17:38--------PURPORT).

There is no distinction made between those who are fit and those who are not fit to hear or take part in the saṅkīrtana movement. It should therefore be preachedwithout discrimination. The only purpose of the preachers of the saṅkīrtana movement must be to go on preaching without restriction. That is the way in which Śrī Caitanya Mahāprabhu introduced this saṅkīrtana movement to the world.
(SRI CAITANYA CARITAMRTA-------1:9:29------PURPORT).

In the impure state of a living being, the various senses are fully engaged in mundane affairs. If the ear is not engaged in the service of the Lord by hearing about Him from Bhagavad-gītā or Śrīmad-Bhāgavatam, certainly the holes of the ear will be filled with some rubbish. Therefore the messages of Bhagavad-gītā and Śrīmad-Bhāgavatam should bepreached all over the world very loudly. That is the duty of a pure devotee who has actually heard about them from the perfect sources. Many want to speak something to others, but because they are not trained to speak on the subject matter of Vedic wisdom they are all speaking nonsense, and people are receiving them with no sense. There are hundreds and thousands of sources for distributing mundane news of the world, and people of the world are also receiving it. Similarly, the people of the world should be taught to hear the transcendental topics of the Lord, and the devotee of the Lord must speak loudly so that they can hear.
(SRIMAD BHAGAVATAM------2:3:20--------PURPORT).

Even if one does not have money, he can preach the Hare Kṛṣṇa mantra to everyone. One can go everywhere, to every home, and request everyone to chant the Hare Kṛṣṇa mantra. Thus the entire world situation will become very happy and peaceful.
(SRI CAITANYA CARITAMRTA-------1:9:44------PURPORT).

By sincere efforts to hear Śrīmad-Bhāgavatam one realizes his constitutional relationship with the Lord in the transcendental humor of servitude, friendship, paternal affection or conjugal love, and by such self-realization one becomes situated at once in the transcendental loving service of the Lord. Not only were all the pure devotees like Nārada self-realized souls, but they were engaged in preaching work automatically by spiritual impetus, and thus they delivered many poor souls entangled in the material modes. They became so powerful because they sincerely followed the Bhāgavatam principles by regular hearing and worshiping. By such actions the accumulated material lusts, etc., become cleansed by the personal endeavor of the Lord within the heart. The Lord is always within the heart of the living being, but He becomes manifested by one's devotional service.
(SRIMAD BHAGAVATAM------2:8:5--------PURPORT).

It is the desire of Lord Caitanya Mahāprabhu that the benevolent activities of the saṅkīrtana movement, which was inaugurated five hundred years ago in Navadvīpa, be spread all over the world for the benefit of all human beings. Unfortunately, there are many so-called followers of Caitanya Mahāprabhu who are satisfied simply to construct a temple, make a show of the Deities, collect some funds and utilize them for eating and sleeping. There is no question of their preaching the cult of Śrī Caitanya Mahāprabhu all over the world. But even though they are unable to do so, if anyone else does it they become envious. This is the condition of the modern followers of Caitanya Mahāprabhu. The Age of Kali is so strong that it affects even the so-called followers of Lord Caitanya. At least the followers of Caitanya Mahāprabhu must come out of India to preach His cult all over the world, for this is the mission of Lord Caitanya. The followers of Lord Caitanya must execute His will with heart and soul, being more tolerant than the trees and humbler than the straw in the street.
(SRI CAITANYA CARITAMRTA-------1:9:47------PURPORT).

The favorable conditions for discharging devotional service are that one should be very enthusiastic in serving the Lord. The Lord in His form of Śrī Caitanya Mahāprabhu wanted the cult of devotional service to the Lord to be preached all over the world, in every nook and corner, and therefore a pure devotee's duty is to discharge this order as far as possible. Every devotee should be very enthusiastic, not only in performing his daily rituals of devotional service, but in trying to preach the cult peacefully by following in the footsteps of Lord Caitanya. If he is not superficially successful in such an attempt, he should not be deterred from the discharge of his duty. Success or failure has no meaning for a pure devotee because he is a soldier in the field. Preaching the cult of devotional service is something like declaring war against materialistic life. There are different kinds of materialists, such as the fruitive workers, the mental speculators, the mystic jugglers, and so many others.
(SRIMAD BHAGAVATAM------2:8:21--------PURPORT).

When a person actually revives his consciousness with thoughts of Kṛṣṇa by the mercy of Śrī Caitanya Mahāprabhu, he revives his spiritual life and becomes addicted to the service of the Lord. Only then can he act as an ācārya. In other words, everyone should engage in preaching, following in the footsteps of Śrī Caitanya Mahāprabhu. In this way one will be very much appreciated by Lord Kṛṣṇa and will quickly be recognized by Him. Actually a devotee of Śrī Caitanya Mahāprabhu must engage in preaching in order to increase the followers of the Lord. By thus preaching actual Vedic knowledge all over the world, one will benefit all mankind.
(SRI CAITANYA CARITAMRTA-------1:7:152------PURPORT).

The devotees of Lord Caitanya must preach Kṛṣṇa consciousness in every village and town in the world. That will satisfy the Lord. It is not that one should act whimsically for his own personal satisfaction. This order comes down through the paramparā system, and the spiritual master presents these orders to the disciple so that he can spread the message of Śrī Caitanya Mahāprabhu. It is the duty of every disciple to carry out the order of the bona fide spiritual master and spread Lord Caitanya's message all over the world.
(SRI CAITANYA CARITAMRTA-------2:16:64------PURPORT).

Everyone wants to act as the proprietor of his actions so that he can enjoy the result. A devotee, however, has no such desire; he acts because the Personality of Godhead wants him to act in a particular way. He has no personal motive. When Lord Caitanya preached Kṛṣṇa consciousness, it was not with the purpose that people would call Him Kṛṣṇa, the Supreme Personality of Godhead; rather, He preached that Kṛṣṇa is the Supreme Personality of Godhead and should be worshiped as such. A devotee who is a most confidential servant of the Lord never does anything for his personal account, but does everything for the satisfaction of the Supreme Lord. It is clearly stated, therefore, mayi sannyasta-karmaṇaḥ: the devotee works, but he works for the Supreme. It is also stated, mayy arpitātmanaḥ: "He gives his mind unto Me." These are the qualifications of a devotee, who, according to this verse, is accepted as the highest of all human beings.
(SRIMAD BHAGAVATAM------3:29:33--------PURPORT).

One who has not listened carefully to the instructions of the spiritual master is unfit for chanting or for preaching the cult of devotional service. One has to water the bhakti-latā-bīja by receiving instructions from the spiritual master.
(SRI CAITANYA CARITAMRTA-------2:19:152------PURPORT).

To make a show of devotional service will not help one. One must be a pure devotee following the devotional process; then one can convert others to devotional service. Śrī Caitanya Mahāprabhu practiced devotional service and preached (āpani ācari' bhakti karila pracāra). If a preacher behaves properly in devotional service, he will be able to convert others. Otherwise, his preaching will have no effect.
(SRI CAITANYA CARITAMRTA-------2:24:98------PURPORT).

When a Vaiṣṇava, pure devotee, tries to be materially opulent and at the same time desires to serve the Supreme Lord, his devotional service is checked. The Lord, in order to show him a special favor, destroys his so-called economic development and material opulences. Thus the devotee, being frustrated in his repeated attempts at economic development, ultimately takes solid shelter under the lotus feet of the Lord. This kind of action may also be accepted as īśa-vidhvaṁ-sitāśiṣām, whereby the Lord destroys one's material opulences but enriches one in spiritual understanding. In the course of our preaching work, we sometimes see that materialistic persons come to us and offer their obeisances to take blessings, which means they want more and more material opulences. If such material opulences are checked, such persons are no longer interested in offering obeisances to the devotees. Such materialistic persons are always concerned about their economic development. They offer obeisances to saintly persons or the Supreme Lord and give something in charity for preaching work with a view that they will be rewarded with further economic development.
(SRIMAD BHAGAVATAM------4:22:36--------PURPORT).

This is the effect of associating with a pure devotee. Our preachers who are preaching Kṛṣṇa consciousness all over the world should follow in the footsteps of Nārada Muni and become purified by following the four principles and chanting the Hare Kṛṣṇa mahā-mantra. This will make them fit to become Vaiṣṇavas. Then, when they speak to sinful people about the teachings of this Kṛṣṇa consciousness movement, people will be affected and take the instructions.
(SRI CAITANYA CARITAMRTA-------2:24:252------PURPORT).

Only an empowered personality can distribute the holy name of the Lord and enjoin all fallen souls to worship Kṛṣṇa. By distributing the holy name of the Lord, he cleanses the hearts of the most fallen people; therefore he extinguishes the blazing fire of the material world. Not only that, he broadcasts the shining brightness of Kṛṣṇa's effulgence throughout the world. Such an ācārya, or spiritual master, should be considered nondifferent from Kṛṣṇa—that is, he should be considered the incarnation of Lord Kṛṣṇa's potency. Such a personality is kṛṣṇāliṅgita-vigraha—that is, he is always embraced by the Supreme Personality of Godhead, Kṛṣṇa. Such a person is above the considerations of the varṇāśrama institution. He is the guru, or spiritual master, for the entire world, a devotee on the topmost platform, the mahā-bhāgavata stage, and a paramahaṁsa-ṭhākura, a spiritual form only fit to be addressed as paramahaṁsa or ṭhākura.”
Nonetheless, there are many people who are just like owls and never open their eyes to see the sunshine. These owlish personalities, who are inferior even to the Māyāvādī sannyāsīs, cannot see the brilliance of Kṛṣṇa's favor upon the mahā-bhāgavata devotee. They are prepared to criticize the person engaged in distributing the holy name all over the world and following in the footsteps of Śrī Caitanya Mahāprabhu, who wanted Kṛṣṇa consciousness preached in every town and city.

(SRI CAITANYA CARITAMRTA-------2:25:9------PURPORT).

Haridāsa Ṭhākura is mentioned here as the most learned scholar, parama-vidvān. Actually, the most important science to know is the science of getting out of the clutches of material existence. Anyone who knows this science must be considered the greatest learned person. Anyone who knows the temporary situation of this material world and is expert in achieving a permanent situation in the spiritual world, who knows that the Supreme Personality of Godhead is beyond the jurisdiction of our experimental knowledge, is understood to be the most learned scholar. Haridāsa Ṭhākura knew this science perfectly. Therefore, he is described in this connection as parama-vidvān. He personally preached the importance of chanting the Hare Kṛṣṇa mahā-mantra, which is approved by the revealed scriptures.

(SRI CAITANYA CARITAMRTA-------3:11:105------PURPORT).

The paramahaṁsa is free from envy. In other stages, even in the householder stage of life, there is competition and envy, but since the activities of the human being in the paramahaṁsa stage are completely engaged in Kṛṣṇa consciousness, or devotional service, there is no scope for envy. In the same order as Kardama Muni, about one hundred years ago, Ṭhākura Bhaktivinoda also wanted to beget a child who could preach the philosophy and teachings of Lord Caitanya to the fullest extent. By his prayers to the Lord he had as his child Bhaktisiddhānta Sarasvatī Gosvāmī Mahārāja, who at the present moment is preaching the philosophy of Lord Caitanya throughout the entire world through his bona fide disciples.

(SRIMAD BHAGAVATAM------3:22:19--------PURPORT).