"There are four Vaisnava sampradayas (systems) of disciplic succession. One sampradaya comes from Lord Brahma, one from the goddess of fortune, one from the Kumaras, headed by Sanat-kumara, and one from Lord Siva. These four systems of disciplic succession are still going on. As King Prthu has illustrated, one who is serious about receiving transcendental Vedic knowledge must accept a guru, or spiritual master, in one of these four disciplic successions. It is said that unless one accepts a mantra from one of these sampradayas, the so-called mantra will not act in Kali-yuga. Many sampradayas have sprung up without authority, and they are misleading the people by giving unauthorized mantras. The rascals of these so-called sampradayas do not observe the Vedic rules and regulations. Although they are addicted to all kinds of sinful activities, they still offer the people mantras and thus mislead them. Intelligent persons, however, know that such mantras will never be successful, and as such they never patronize such upstart spiritual groups. People should be very careful of these nonsensical sampradayas. To get some facility for sense gratification, unfortunate people in this age receive mantras from these so-called sampradayas."
Srimad-Bhagavatam 4:17:5 Purport
"In the parampara system, the instructions taken from the bona fide spiritual master must also be based on revealed Vedic scriptures. One who is in the line of disciplic succession cannot manufacture his own way of behavior. There are many so-called followers of the Vaisnava cult in the line of Caitanya Mahaprabhu who do not scrupulously follow the conclusions of the sastras, and therefore they are considered to be apa-sampradaya, which means "outside of the sampradaya." Some of these groups are known as aula, baula, kartabhaja, neda, daravesa, sani sahajiya, sakhibheki, smarta, jata-gosani, ativadi, cudadhari and gauranga-nagari. In order to follow strictly the disciplic succession of Lord Caitanya Mahaprabhu, one should not associate with these apasampradaya communities."
Caitanya-caritamrta, Adi lila 7:48
"Such transcendental relationships with the Supreme Lord cannot be manufactured by the mental concoctions of pseudo-devotees. In Bhakti-rasamrta-sindhu (1.2.101) Rupa Gosvami has stated that devotional service that makes no reference to Vedic scriptures or Vedic literatures and that does not follow the principles set forth therein can never be approved. Sri Bhaktisiddhanta Sarasvati Gosvami Maharaja has also remarked that professional spiritual masters, professional Bhagavatam reciters, professional kirtana performers and those engaged in self-concocted devotional service cannot be accepted. In India there are various professional communities known as Aula, Baula, Kartabhaja, Neda Daravesa, Sani, Atibadi, Cudadhari, and Gauranganagari. A member of the Ventor Gosvami Society, or the caste called gosvami, cannot be accepted as a descendant of the six original Gosvamis. Nor can so-called devotees who manufacture songs about Lord Caitanya, nor those who are professional priests or paid reciters, be accepted. One who does not follow the principles of pancaratra, or one who is an impersonalist or addicted to sex life, cannot be compared with those who have dedicated their lives to the service of Krsna. A pure devotee who is always engaged in Krsna consciousness can sacrifice everything for the service of the Lord. One who has dedicated his life to the service of Lord Caitanya, Krsna and the spiritual master, or a person who is following the principles of householder life, as well as one following the principles of the renounced life in the order of Caitanya Mahaprabhu, is a devotee and cannot be compared to professional men."
Teachings of Lord Caitanya, Chapter 29
"Yata mat tata patha: "I can manufacture my own way." This rascaldom has been condemned by Srila Rupa Gosvami. He says that harer bhaktih... You will find many so-called bhaktas crying, falling down on the ground. But immediately after, he is smoking bidi. So why this is going on? Because they do not follow the injunction of Srila Rupa Gosvami. Chanting, dancing very loudly, and after the performance is finished--I have seen it--"Can you give me a bidi?" You see? "My throat is now dried up." So this is utpata. Srila Rupa Gosvami has described this kind of so-called devotional attitude is simply disturbance. They imitate. Imitate. Therefore Srila Bhaktivinoda Thakura has condemned. There are so many apa-sampradaya going on in the name of Caitanya Mahaprabhu's devotee. Who are they? Aula, baula, karttabhaja, neda, daravesa, sani, sahajiya, sakhibheki, smarta, jata-gosani. Then ativadi, cudadhari, gauranga-nagari, tota kahe ei tara sanga nahi kori: Tota Babaji, he says, "I do not associate with these classes of men." So after disappearance of Sri Caitanya Mahaprabhu, so many apa-sampradaya sprang up. So we should be very much careful that... Sampradaya means who are carefully following the Vedic principle."
Srila Prabhupada Lecture on Caitanya-caritamrta, 03-27-75, Mayapur
"In this way there was, Caitanya's Mahaprabhu's time, this Krsna consciousness movement was going nicely, very. And after Him, there was six Gosvamis. They also managed. Then, as it is the rule of this material world that you start something very good but in due course of time the things deteriorate, so this Vaisnava, Krsna consciousness movement, also deteriorated in due course of time. Say, after the disappearance of the Gosvamins, about 250 years after, the things became most ridiculous. The so-called devotees... Their representatives still are continuing. They are called prakrta-sahajiya. Prakrta-sahajiya means taking things very easily. They thought that Radha-Krsna is just like a boy and girl's lusty affairs. And in this way they took it that sex life as religion. Even Vivekananda, he also criticized, "Vaisnavism is sex religion." So the things deteriorated in such a way..."
Srila Prabhupada Lecture, 02-07-69, Los Angeles
Bhaktivedanta Book Trust. HDG A.C. Bhaktivedanta Swami Srila Prabhupada.