(Srila Prabhupada in New York City, 1966—click to enlarge)
"In executing penance, one must be determined to return home, back to Godhead, and must decide to undergo all types of tribulations for that end. Even for material prosperity, name and fame, one has to undergo severe types of penance, otherwise no one can become an important figure in this material world. Why, then, are there severe types of penance for the perfection of devotional service? An easygoing life and attainment of perfection in transcendental realization cannot go together. The Lord is more clever than any living entity; therefore He wants to see how painstaking the devotee is in devotional service. The order is received from the Lord, either directly or through the bona fide spiritual master, and to execute that order, however painstaking, is the severe type of penance. One who follows the principle rigidly is sure to achieve success in attaining the Lord's mercy."
(Srimad-Bhagavatam 2.9.24, Purport)
"Good things do not come so easily; you know the difficulties that I encountered in my first year in your country. Sometimes I did not even know where I was to live, neither when I came did I have any friends. But I was always determined that somehow I would do everything possible to fulfill the desire of my Guru Maharaj, and despite all difficulties I always remained enthusiastic."
(Srila Prabhupada Letter, January 5, 1972)
"My Guru Maharaj gave me a task and always I was discouraged by my god-brothers, but I did not forget him even for a moment, and I was determined to follow my duty, even though sometimes I did not like to do it."
(Srila Prabhupada Letter, November 5, 1972)
"I am very much encouraged that despite so many difficulties and tricks of Maya that you are still desiring Krishna so much. Thank you very much. In order to attain the topmost perfection of this human form of life one simply has to try for Krishna with enthusiasm and patience, and all obstacles will be overcome. If you are determined in this way to be His devotee, Krishna will provide some happy solution. But even if He puts us into extreme difficulty, we must always be prepared to consider everything as His special Mercy, that He is testing my sincerity, or that this trouble is nothing to what I deserve."
(Srila Prabhupada Letter, November 17, 1971)
"There are many examples in history of persons who have been very much disabled physically, but still have executed Krishna Consciousness. Still, up to date in places like Vrndavana, India, there are many persons who are blind, crippled, lame, deformed, etc., but they are determined to practice Krishna Consciousness to their best ability. So, you should also do like that. Simply be determined to practice the process of Bhakti-yoga with whatever abilities you may have. If you are really sincere, then Krishna will give you help."
(Srila Prabhupada Letter, June 30, 1975)
"The mercy the Lord bestows upon a particular person engaged in executing the responsible work entrusted unto him is beyond imagination. But His mercy is received due to our penance and perseverance in executing devotional service."
(Srimad-Bhagavatam 3.9.30, Purport)
"We are trying to please Krishna. That is all. We simply must go on with our business, to the best of our ability. We must always sincerely try to do our best with great determination. This is the transcendental position. Success or failure, this is not our business. We leave that up to Krishna."
(Srila Prabhupada Letter, February 15, 1973)
"The key to success in spiritual life is to always endeavor to please the Spiritual Master, and follow his instructions. One who is determined in this effort will advance very quickly in Krishna consciousness."
(Srila Prabhupada Letter, February 20, 1972)
"Our determination should be to serve the previous guru and acarya. Evam parampara-praptam (BG 4.2). That is our determination. Tandera carana-sevi. Our service... Not directly Krishna. Because to serve Vaiṣṇava is more than serving Krishna directly. Mad-bhakta-pujabhyadhika (SB 11.19.21). Krishna likes that. He doesn't accept anyone's service directly. That is a gross mistake. Therefore Narottama dasa Thakura is teaching us... (break) ...trying to become one with Krishna or one with the gopis. These are all Mayavada philosophy. Tandera carana-sevi. You have to serve the servant of Krishna, tad bhrtya dasa-dasa-dasanudasah (CC Madhya 13.80). That is the way. Not directly."
(Srila Prabhupada Lecture, Vrindavan, October 4, 1976)
"So Krishna, when instructs from within the heart, He is called caitya-guru. And that caitya-guru is expanded by the process, personal presentation of spiritual master. So both ways He is helping us. Krishna is so kind. Guru-krsna-krpa. Krishna is helping from within, but sometimes we are so dull, naturally, that we cannot understand. Therefore He sends His representative to instruct externally. So He is helping internally and externally. There is no difference between the internal and external instructor. We should take advantage of this instruction. That is called vyavasayatmika buddhih, fixed-up resolution. Fixed-up resolution. If we become fixed up in this resolution, that 'Whatever we have heard from my guru, the representative of Krishna, I must execute. I do not care for my personal convenience or inconvenience. This is my life and soul,' then your life is perfect."
(Srila Prabhupada Lecture, Mayapur, October 28, 1974)
"You are setting the example of determination which others may see and follow. In this way, go on increasing and such sincerity is noticed by Krishna and He is helping you to approach nearer and nearer to His Lotus Feet."
(Srila Prabhupada Letter, January 21, 1972)
"I am glad to note your determination to be freed from the material entanglement by chanting Hare Krishna mantra. This is the recommended process for this age of disagreement for achieving Krishna consciousness. It is authorized, very easy, and it does not cost anything. I understand that you have got japa beads, so this is very good that you are seriously taking to the process. So if you continue Krishna will bless you, and you will go back home back to Godhead. I also understand that you have Bhagavad gita As It Is, so try to read something regularly, but do not neglect the chanting, that is the important thing."
(Srila Prabhupada Letter, October 29, 1975)
"This is very much wanted throughout the society of men, that some few of you will come to the understanding that by serving the Lord with my full energy that this will be my happy position of life and that no other occupation will give me any, not even an ounce of pleasure. Such persons like yourself who are thinking in this way are getting all intelligence and facility by how to do the things properly, and that Krishna is helping you with intelligence and ability, now you take the right course and utilize the opportunity given to you by Krishna to actually inject the human society with that same determination to serve the Lord. Only a handful of you are there who are convinced beyond any doubt about this Krsna consciousness movement, but is sufficient to change the entire course of history."
(Srila Prabhupada Letter, July 3, 1972)
"So go on in this way, serving your spiritual master to best of your capacity, and remaining always fixed and steady in your determination to fulfill the goal of your life, namely, to go back to home, back to Godhead, without further delay."
(Srila Prabhupada Letter, January 9, 1973)