Chanting Hare Krishna is the most sublime method of reviving our original spiritual consciousness. A sincere practitioner must be careful not to hear such chanting from the lips of non-devotees, who do not come in the disciplic succession and who derride a bona fide spiritual master and his instructions as such chanting has a contaminating effect. The following are various quotes by His Divine Grace A.C.Bhaktivedanta Swami Prabhupada, the founder of the Hare Krishna movement on this topic.
The first and foremost offence is the act of defaming the great saints who have glorified the chanting of the Name of the Lord by example in their own life and precepts. According to ordinary moral principles no one must be defamed for serving any ulterior motive. But still according to the gravity of different offences, defamation of Saints who have done much for the propagation of the Name of God and His Fame must be considered the gravest of all offences. Those who are therefore accustomed to defame such saints, are spiritually great offenders and such persons can have no access to the transcendental Name of the Lord. We should therefore be guard against such offence.
BTGPY1f: The Science of Congregational Chanting of the Name of the Lord (Samkirtan)
The devotee must receive the transcendental Name of the Lord from the transcendental lips of a bonafide spiritual master who is cent percent devotee of the Lord and nothing more or nothing less and then begin chanting the transcendental Name of the Lord by constant repetition. Such spiritual master as above mentioned is known as the Guru from whom either initiation is taken or the one from whom spiritual instruction is received. One should have unflinching faith in such self realised transcendental spiritual master. The bonafides of such spiritual master can however be known, by their activities only which are always evident in respect of everything being done for and on behalf of the Lord. The self-realised spiritual master never deviates from the rulings of Shastras (Law Books) and he always does in practice what he speaks in theory. Those who however manufacture spiritual lessons from their own fertile brain, without having undergone any spiritual training from a bonafide spiritual master, cannot be counted as a spiritual master. Disrespect for such bonafide spiritual master and respect for the pseudo-spiritual master both are offences of the third order.
BTGPY1f: The Science of Congregational Chanting of the Name of the Lord (Samkirtan)
While describing the system of protection for the creeper of devotional service, Sri Caitanya Mahaprabhu has especially stressed protection from offenses unto the lotus feet of Vaisnavas. Such offenses are called vaisnava-aparadha. Aparadha means "offense." If one commits vaisnava-aparadhas, all of his progress in devotional service will be checked. Even though one is very much advanced in devotional service, if he commits offenses at the feet of a Vaisnava, his advancement is all spoiled.... Therefore one should be very careful about committing offenses at the feet of a Vaisnava. The most grievous type of vaisnava-aparadha is called guru-aparadha, which refers to offenses at the lotus feet of the spiritual master. In the chanting of the holy name of the Supreme Personality of Godhead, this guru-aparadha is considered the most grievous offense.
(Srimad-Bhagavatam 4.21.37)
First offense is guror avajna, defying the authority of guru. This is the first offense. So one who is offensive, how he can make advance in chanting? He cannot make. Then everything is finished in the beginning. Guror avajna. Everything is there. If one is disobeying the spiritual master, he cannot remain in the pure status of life. He cannot be siksa-guru or anything else. He is finished, immediately. Guror avajna sruti-sastra-nindanam, namno balad yasya hi... You do not study all these things. You become initiated. There are ten kinds of offenses. Do you have any regard for these things or not? You must avoid these ten kinds of offenses. The first offense is to disobey the orders of guru. That is first offense. So if you are offensive, how you can become advanced by chanting? That is also not possible.
(Bhagavad-gita 17.1-3 -- Honolulu, July 4, 1974)
So don't spoil the movement by manufacturing ideas. Don't do that. Go on in the standard way, keep yourself pure; then movement is sure to be successful. But if you want to spoil it by whimsical, then what can be done? It will be spoiled. If you manufacture whims and disagree and fight amongst yourself, then it will be another edition of these so-called movements. It will lose the spiritual strength. Always remember it. You cannot.... Now, actually, people are surprised: "What this Hare Krsna mantra has got power that it is changing so quickly?" And on the other hand, it is to be admitted, unless it has got power, how it is changing? So we have to keep that power. Don't make it an ordinary musical vibration. It is a different thing, spiritual. Although it seems like musical vibration, but it is spiritual, completely. Mantrausadhi-vasa. Even, by mantra, the snakes can be charmed. So mantra is not ordinary sound vibration. So we have to keep the mantra in potency, potent, by offenseless chanting, by remaining pure. If you pollute the mantra, then it will lose its effect.
Room Conversation -- April 27, 1976, Auckland, New Zealand
The guru does not manufacture a new process to instruct the disciple. The disciple receives from the guru an authorized process received by the guru from his guru. This is called the system of disciplic succession (evam parampara-praptamm imam rajarssayo viduhh). This is the bona fide Vedic system of receiving the process of devotional service, by which the Supreme Personality of Godhead is pleased. Therefore, to approach a bona fide guru, or spiritual master, is essential. The bona fide spiritual master is he who has received the mercy of his guru, who in turn is bona fide because he has received the mercy of his guru. This is called the parampara system. Unless one follows this parampara system, the mantra one receives will be chanted for no purpose.
SB 8.16.24
Prabhupada: As soon as the discipline broken, then everything is lost. Now you can dance like a dog. That will not affect. Nobody can do that unless there is spiritual strength. Now, last night Madhudvissa Maharaja was singing, and so many men became enthused to dance. So unless there is spiritual strength, it cannot be done. Others cannot ask and dance. No, that is not possible. That is not possible. Unless there is spiritual strength, you cannot enthuse others. So we should have to acquire spiritual strength by following the regulative principle. Sanatana Gosvami has therefore forbidden. Avaisnava-mukhodgirnnam puta-hari-kathamrrtam sravanam kartavyam: "Those who are not following Vaisnava principles, one should not hear from him." Why? It is Krsna-katha, Krsna's. Now sarpocchista-payo yatha: "Milk is very good, but as soon as it is touched by a serpent, it is no more good. It is harmful." So one must be Vaisnava. Unless one is Vaisnava, there is injunction, "Don't hear from him. It will be poisonous." So one who is not following Vaisnava principle, he cannot speak about Vaisnava principle. It is harmful. That is forbidden by acaryas, Sanatana Gosvami. If somebody says, "What is the harm? He is chanting Hare Krsna..." He cannot chant. That is a show-bottle chant. That is not effective. But even taking that "Anyone who is chanting, let me hear," no, Sanatana Gosvami says, "No, don't hear." It will be harmful more than... In other words, if you are not following the Vaisnava principle, you don't chant. It will not be effective
(Room Conversation with Bhurijana dasa and Disciples -- July 1, 1974, Melbourne)
Yoko Ono: If the mantra itself has such power, does it matter where you receive it, where you take it?
Prabhupada: Yes. Yes. That is a fact. The example is given just like milk. Milk is nutritious. That's a fact. Everyone knows. But if the milk is touched through the tongue of a serpent, it is no more nutritious. It is poison.
Yoko Ono: Well, milk is material.
Prabhupada: No, material. You want to understand through your material senses, we have to give...
Yoko Ono: Well, no. I don't have, you don't have to tell me material senses. I mean mantra is not material. It should be something spiritual, and therefore nobody can spoil it, I don't think. I mean, I wonder if anybody can spoil something that is not material.
Prabhupada: But the thing is that if you don't receive the mantra through the proper channel, it may not be mantra.
John Lennon: But how would you know, anyway? How are you able to tell, anyway? I mean, for any of your disciples or us or anybody that goes to any spiritual master, how are we to tell...
Prabhupada: Not any spiritual master.
John Lennon: True master. How are we to tell one from the other?
Prabhupada: It is not that any spiritual master. Sampradaya. Sampradaya means a particular line of disciplic succession.
Room Conversation With John Lennon, Yoko Ono, and George Harrison -- September 11, 1969, London, At Tittenhurst
A person who cannot keep his faith in the words of his spiritual master but acts independently never receives the authority to chant the holy name of the Lord. It is said in the Vedas (Svetasvatara Upanisad 6.23):
yasya deve para bhaktir
yatha deve tatha gurau
tasyaite kathita hy arthah
prakasante mahatmanahh
"Only unto those great souls who have implicit faith in both the Lord and the spiritual master are all the imports of Vedic knowledge automatically revealed." This Vedic injunction is very important, and Sri Caitanya Mahaprabhu supported it by His personal behavior. Believing in the words of His spiritual master, He introduced the sankirtana movement, just as the present Krsna consciousness movement was started with belief in the words of our spiritual master. He wanted to preach, we believed in his words and tried somehow or other to fulfill them, and now this movement has become successful all over the world. Therefore faith in the words of the spiritual master and in the Supreme Personality of Godhead is the secret of success. Sri Caitanya Mahaprabhu never disobeyed the orders of His spiritual master and stopped propagating the sankirtana movement. Sri Bhaktisiddhanta Sarasvatī Gosvami, at the time of his passing away, ordered all his disciples to work conjointly to preach the mission of Caitanya Mahaprabhu all over the world. Later, however, some self-interested, foolish disciples disobeyed his orders. Each one of them wanted to become head of the mission, and they fought in the courts, neglecting the order of the spiritual master, and the entire mission was defeated. We are not proud of this; however, the truth must be explained. We believed in the words of our spiritual master and started in a humble way-in a helpless way—but due to the spiritual force of the order of the supreme authority, this movement has become successful.
It is to be understood that when Sri Caitanya Mahaprabhu chanted and danced, He did so by the influence of the pleasure potency of the spiritual world. Sri Caitanya Mahaprabhu never considered the holy name of the Lord to be a material vibration, nor does any pure devotee mistake the chanting of the Hare Krsna mantra to be a material musical manifestation. Lord Caitanya never tried to be the master of the holy name; rather He taught us how to be servants of the holy name. If one chants the holy name of the Lord just to make a show, not knowing the secret of success, he may increase his bile secretion, but he will never attain perfection in chanting the holy name.
CC adi 7.95-96
"The letters of the holy name have so much spiritual potency that they act even when uttered improperly.
PURPORT
Srila Bhaktisiddhanta Sarasvati Thakura states that the word vyavahita ("improperly uttered") is not used here to refer to the mundane vibration of the letters of the alphabet. Such negligent utterance for the sense gratification of materialistic persons is not a vibration of transcendental sound. Utterance of the holy name while one engages in sense gratification is an impediment on the path toward achieving ecstatic love for Krsna.
Antya 3.59
Sri Caitanya Mahaprabhu is herein pointing out to the brahmana that Mayavadi philosophers cannot understand that the living entity is equal in quality with the Supreme Personality of Godhead. Because they do not accept this, they think that the living entity has been falsely divided from the original Brahman due to being conditioned by maya. Mayavadis believe that the Absolute Truth is ultimately impersonal. When an incarnation of God or God Himself comes, they think He is covered by maya. In other words, Mayavadi impersonalists think that the Lord's form is also a product of this material world. Due to a poor fund of knowledge, they cannot understand that Krsna has no body separate from Himself. His body and Himself are both the same Absolute Truth. Not having perfect knowledge of Krsna, such impersonalists certainly commit offenses at His lotus feet. Therefore they do not utter the original name of the Absolute Truth, Krsna. In their impersonal way, they utter the name of impersonal Brahman, spirit soul. In other words, they indulge in indirect indications of the Absolute Truth. Even if they happen to utter the name of Govinda, Krsna or Madhava, they still cannot understand that these names are as good as Govinda, Krsna or Madhava the person. Because they are ultimately impersonalists, their uttering of the personal name has no potency. Actually they do not believe in Krsna but consider all these names to be material vibrations.
Cc mad 17.132
Sree Krishna has said Himself while addressing Narada that He does not necessarily make Himself immobile by His situation in the transcendental world, neither He is so, being seated in the hearts of the Yogins as Paramatma and so forth, but He resides surely in His fullness, where His devotees chant the transcendental Name in right earnestness. Sree Krishna being the absolute enjoyer as stated in the Geeta,
"Aham eba saraba yajnanam bhokta cha Prabhur eba cha"
i.e., "I am the Absolute Enjoyer and Master of all Yajnas or sacrifices etc."-He cannot be the object of our sense-pleasure in combination with music and bands and called thereof "Samkirtan." He cannot be enjoyed by our irresponsible whims and feats. He says therefore that He lives only there where His devotees chant His Name.
"Mad bhakta jatra gayantee"
He declines to descend Himself where there is dearth of His devotees. Because His devotees never try to enjoy Him or His Paraphernalia in a pseudo-spiritualistic mode. His devotee knows it perfectly well that Sree Krishna being the Absolute Personality of Godhead i.e., "Purushottama" as stated in the Geeta, He cannot consent to reside at a place where His transcendental Name, Fame, Quality, etc., are considered as equal with mundane names, etc., and thereby treated with all undevotional manner.
BTGPY1f: The Science of Congregational Chanting of the Name of the Lord (Samkirtan)
Impersonalists also sometimes chant the Hare Krsna mantra and dance, but their aim is not to serve the Lord. It is to become one with the Lord and merge into His existence.
NOD Devastation