"Your final question is how can you become a pure devotee, and the answer to this is given in Bhagavad-gita. Krishna instructs Arjuna that the mahatma, the pure devotee, is he who has fully surrendered himself unto the spiritual nature. And how can we tell if one is completely surrendered unto the spiritual nature? He is always fully engaged in devotional service to Krishna. So this is the process of becoming a pure devotee. We have to engage all of our words, thoughts, and activities in Krishna Consciousness under the direction of the Spiritual Master. Therefore, at every moment you should be busy in some way in serving Krishna and His pure devotees, and automatically you will become purified in Krishna Consciousness. Krishna is always willing to shower His mercy upon His devotees, so we have simply to become receptive to this mercy by devotional service, and then the path is very easy."
(Srila Prabhupada Letter, June 16, 1969)
"Regarding your question about offering Prasadam, whatever is offered to the Deity actually it goes through the Spiritual Master. The Spiritual Master offers to Lord Chaitanya, and Lord Chaitanya offers it to Krishna. Then Radha Krishna eats, or Jagannath eats, then Chaitanya Mahaprabhu eats, then the Spiritual Master eats, and it becomes Mahaprasadam. So when you offer something, you think like that and chant the Gayatri mantra, and then everything is complete. At last, ring the bell, take out the plate and wipe the place where the plate was kept.
Regarding your last question about the ecstatic symptoms of chanting Hare Krishna, you should know that the Hare Krishna Mantra has an equal effect upon all devotees. Just like the sunshine has an equal effect on everyone, but when it is covered, the sunshine has a different effect. Similarly, the influence of the Hare Krishna Mantra becomes manifest when one is no longer covered by the ten offenses to chanting. The more we become free from the ten offenses, the more the effect of chanting becomes manifested through us. Everyone can become a great devotee, being freed from the offenses 100%, simply by one's determination and effort."
(Srila Prabhupada Letter, June 16, 1969)
"You have inquired why Chaitanya Mahaprabhu has not mentioned anything about accepting a Spiritual Master in His Siksastaka. But perhaps you have missed the point that He says amanina manadena kirtaniya sada hari. This means one has to chant the Holy Names of Krishna, becoming humbler than the straw, and more tolerant than the tree. So who can become humbler than the straw unless he accepts a Spiritual Master? The whole world is puffed up. Everyone wants to become the Lord of everything. Ultimately, the Mayavadi philosopher wants to become one with the Supreme Lord. This means that when one fails to become Lord of everything, he wants to mix up with the Supreme Lord and tries in that way to automatically become Lord of everything. What he can't perform by his own capacity he wants to have done by being merged into the Supreme Lord. That is the mentality of the general people. But if anyone becomes humbler than the grass and more tolerant than the tree, it is understood that he has accepted a Spiritual Master. Besides that, if we accept Sikshastak as authority given by Lord Chaitanya, this means we accept Lord Chaitanya as Spiritual Master. In the Bhagavad-gita it is openly mentioned that Arjuna accepted Krishna as the Spiritual Master. There is another mention in the Sikshastak, Lord Chaitanya says 'I do not want any wealth of this world, I do not want any following, neither do I want a beautiful wife. Simply I want to become a servant of the Lord.' To become the servant of the Lord means to accept a Spiritual Master. Without accepting somebody as master, how can one become an expert servant? It is not that in every literature you will find the words that everyone has to accept a Spiritual Master, but we have to study things scrutinizingly. In the Chaitanya Charitamrta there is mention guru krsna krpaya paya bhakti lata bija (CC Madhya 19.151). By the mercy of the Spiritual Master and Krishna one can get the seeds of bhakti lata, the plant of devotional service."
(Srila Prabhupada Letter, July 4, 1969)
"Regarding your question about marriage, the thing is that as I am a sannyasi, I am not concerned with family life, but because I want to see my disciples very happy in Krishna Consciousness, therefore, those who are feeling some sexual disturbance are requested by me to get themselves married. Another principle is that those who are brahmacaris, they should sacrifice all of their income and collection for the Krishna Consciousness Movement, whereas those who are married should work, earning money as much as possible, and at least 50% should be spent for the Krishna Consciousness Movement. So we have no objection for allowing you to get married, but it is up to you to consider if you will work hard and earn money both for Krishna and for your family. You cannot get married, and at the same time do not earn money. Of course, by preaching Sankirtana Movement, if you are satisfied with a small income, that is also nice."
(Srila Prabhupada Letter, July 5, 1969)
"Regarding your question, 'what is the difference between the spirit souls comprising the Brahma jyoti and the spirit souls here in Maya?', in the Brahma jyoti the spirit souls on account of their impersonal views are devoid of a body, exactly like here in Maya there are ghosts who are devoid of any gross bodies. The ghost being devoid of a body, he suffers terribly because he is unable to satisfy his senses. The spirit souls in the Brahma jyoti, although they have no desire for sense gratification, still they feel inconvenience like the ghost, and they fall down again in the Maya's atmosphere and develop a material body. In the Bhagavat therefore it is said that persons who are impersonalists and do not develop the dormant devotional attitude, their intelligence is not pure, because for want of a spiritual body, they come down again to the material world. In the Bhagavad Gita it is clearly said by the Lord that the only way of not coming back to the material world is to be promoted to the spiritual planets. For the impersonalists there is no such assurance of not falling down in the whole Vedic literature. The conclusion is that without developing the spiritual body and without being situated on one of the spiritual planets, the so-called liberation is also illusion, or it is not complete. A spirit soul who falls down from the Brahma jyoti to the Kingdom of Maya may have a chance of associating with a pure devotee, and then he may be elevated to the spiritual planets of Vaikuntha or to Goloka Vrindaban. From the Brahma jyoti there is no direct promotion to the spiritual planets, and it is clearly stated in the Bhagavatam that such souls fall down: patantyvadha."
(Srila Prabhupada Letter, July 24, 1969)
"Regarding your question about Krishna's Name, the first principle is that Krishna is Absolute. He is not only identical with His Name, but with His Qualities, Form, Pastimes, Paraphernalia, etc. Krishna is identical with the whole creation because the creation means the expansion of Krishna's energy. The energy is never different from the source of the energy as much as heat and light are never different from the fire. The quality of fire is there existing both in heat and light. Naturally Krishna is not different from anything, and what to speak of His Transcendental Name? This is explained in the Bhagavad Gita where Krishna says that 'everything is resting on Me, but I am not everything.' This simultaneously one and different philosophy should be carefully understood. Then our Krishna Consciousness will be more clear.
Regarding Lord Jagannath, He is the unfinished carved form of Krishna. One king named Indradyumna wanted to establish a Jagannatha temple some thousands of years ago, but while the Deities were being carved by the heavenly carpenter, Visva Karma, the king was in too much haste, and he established the half-finished Deities in the temple. Jagannath means the Lord of the universe. That is Krishna. Krishna as the only one Lord of everything is confirmed in the Brahma Samhita, Srimad Bhagavatam, Bhagavad Gita, Chaitanya Charitamrta, and all Vedic literature. Rathayatra is celebrating the occasion when Lord Krishna, or Lord Jagannath attended one religious functional occasion in Kuruksetra along with His elder brother and younger sister in a big chariot.
So far as your question about controversy amongst the disciples of Bhaktisiddhanta Sarasvati Goswami Maharaj, that is a fact. But this controversy is not material. Just like in a national program, different political parties are sometimes in conflict and make propaganda against each other, but their central point is always service to the country. Similarly, amongst the disciples of Bhaktisiddhanta Sarasvati there may be some controversy, but the central point is how to preach the mission of His Divine Grace. If the central point is fixed up then there is no harm in such controversy. Every individual being must have his opinion; that is the significance of individuality, but all such differences of opinions must coincide in Krishna. In the battlefield of Kuruksetra were Arjuna and Bhisma who were fighting with one another, and because Krishna was on the side of Arjuna, sometimes Bhisma pierced the body of Krishna also with arrows. But still they remained the greatest devotees of the Lord, and Krishna accepted the friendship of Arjuna just as He accepted the inimical arrows of Bhisma in the same loving spirit. So you do not be disturbed by such controversial points. Better you engage your mind very seriously in the matter of the service entrusted upon you. That will make you progressive in Krishna Consciousness."
(Srila Prabhupada Letter, July 28, 1969)