Imam Al-Barbaharee (may Allah have mercy upon him, died 329 AH) said:
“Know that there has never emerged a heresy or innovation except from the ignorant rabble who follow anyone who calls out wildly. They bend with every wind that blows – so anyone who is like that has no religion. Allāh, the Mighty and Majestic said: «They did not differ until after the knowledge came to them [and then they differed] through envy among themselves.» [Al-Jāthiyah: 19] And they are the scholars of evil, the people of greed and innovation.”
Shaikh Rabee’ Al-Madkhalee (may Allah preserve him) commented:
“They are the scholars of evil, the people of greed and innovation…” “Meaning: regardless of who it is, he is a person of misguidance. And it is not permitted for a Muslim to follow these groups from the People of Misguidance (ahlud-dalāl) – those who sell the verses of Allāh for a meagre price. They oppose the Book of Allāh and the Sunnah of the Messenger (ﷺ) – [and this whilst they know] the plainness of the verses, and the clear proofs in the establishment of the truth, the clarification of the truth in every field of knowledge in which the people of differing have differed: whether in the arena of the Names and Attributes, in the arena of the promises of reward and threats of punishment, in the arena of Imān and its reality, in the arena of Al-Qadr and other than that.
So the people of all innovations are nothing except rabble and riffraff. Some of the scholars have stated, and from them Ibn Hajr and Ash-Shātibee: “The innovator is not a scholar.” The innovator is not a scholar even if he possesses something of knowledge since his knowledge is corrupted. He cannot be relied upon and he is not counted amongst the the scholars regardless of whether he preaches sermons, and makes noise or is proud and pompous, since he is still a ignoramus because his knowledge did not benefit him. And for this reason Allāh’s Messenger would seek refuge from knowledge that does not benefit, and from a heart that does not submit with humility, and from a supplication that is not answered.  So the knowledge that does not benefit is more harmful to a person than ignorance. And we seek refuge with Allāh…” Muslim, no. 2722 from the hadeeth of Zayd Ibn Arqam (radiyallāhu ‛anhu).
«They did not differ until after the knowledge came to them [and then they differed] through envy among themselves.» “Differing occurred amongst them (i.e. the People of the Book) after knowledge had come to them. And likewise Ahlul-Bid‛a have a share in this verse, many of them, not all of them; meaning, many of them live upon ignorance and doubts, and the truth is not clear to them. Some of them continue in their falsehood even after the truth is made clear to them, and they remain upon falsehood. For this reason Al-Imām Ibn Taymiyyah (rahimahullāh) stated: “Many of the heads of innovation have hypocrisy or are hypocrites.”  The thought that hypocrisy ended after the time of the Messenger (ﷺ) is erroneous for the people of innovation have many heretics (zanādiqah) and hypocrites (munāfiqoon) in their ranks. For this reason you will find amongst them innovations that you would not find even in the Jews and Christians. It is for this reason the Al-Bukhāree reports in Khalq Af‛ālil-‛Ibād from numerous scholars that the Jahmiyyah are more evil in their misguidance than the Jews and Christians, and the other religions. That is because the Jews, Christians and the other religions say: that Allāh is above the heavens; and has ascended over the Throne – yet the Jahmiyyah say: Allāh is in every place. So their saying is worse than that of the Jews and Christians and the rest of the religions in this matter. And for this reason the scholars declared the Jahmiyyah to be unbelievers.
And likewise there is found amongst the Qadariyyah (the deniers of the pre-Decree) stubborn opposers of the truth (mu‛ānideen); likewise amongst the Mu‛tazilah there are mu‛ānideen (stubborn opposers); also amongst the extreme Murji’ah there are mu‛ānideen (stubborn opposers); amongst all of Ahlul-Bid‛ah there are extremists, stubborn opposers of the truth. And there is found amongst them the rabble – and this rabble and riffraff, we do not declare them to be unbelievers. So these people are not declared unbelievers by us except those upon whom the proof is explicitly established, and that we are acquainted with him specifically – and this alongside the fact that we know there is amongst them hypocrites – but we cannot specifically declare particular individuals to be outside of Islām [except after the proof is established].
In these times we believe that the Salafi Da‛wah has become widespread. Many of the people of innovation and misguidance are acquainted with it, yet they still abstain from it out of stubbornness. These people know that the Salafi Da’wah is the truth in the arena of the Names and Attributes of Allāh, in the arena of the Pre-Decree and in all of the arenas of knowledge, yet they still oppose it. So [those with beliefs that exit one from Islam] are unbelievers because the proof has been established upon them. However, we are not able to single out individuals from amongst them [since we do not know in specific upon whom the proof has been established]. So there are many amongst them upon whom the proof has been established [due to the Salafi Da’wah reaching them]. And many are also masākeen, ignorant folk, rabble and riffraff, followers of anyone who yells out to them just as the author, Al-Barbahāree, has stated (rahimahullāh) – so none are declared unbelievers except for the one to whom knowledge had reached and the proof established.” Ibn Taymiyyah (rahimahullāh) stated in Majmoo’ al-Fatāwā (3/353): “There is amongst ahlul-bid‛a the hypocrite and the heretic, so this one is an unbeliever. The likes of this are plentiful amongst the Rāfidah and the Jahmiyyah – and their heads were indeed hypocrites and heretics. The first person to innovate the Rāfidee creed was a hypocrite, and likewise with the Jahmee creed. So their origin lies in heresy and hypocrisy. And it is for this reason that there are also heretics and hypocrites from the sects of the Qarāmitah, the Bātiniyyah, the Philosophers and their likes who incline towards the Rāfidah and the Jahmiyyah due their nearness to them. And from ahlul-bid‛a there maybe a person who has īmān both inwardly and outwardly. However, he has ignorance and transgression such that he errs in what he errs, in opposition to the Sunnah. This one is neither an unbeliever nor a hypocrite. There also may emanate from him sin and oppression and due to it he is a fāsiq (a sinner) or one who is disobedient. He may be mistaken, with misinterpretations [of the texts] who is forgiven his mistake. And it is possible that alongside this, he has with him of īmān and taqwa such that he has an allegiance to Allāh in accordance to his īmān and taqwā.”
Shaikh Salih al-Fawzan (may Allah preserve him) commented:
“Know that there has never emerged a heresy…” So heresy is hypocrisy, and it is to make apparent one’s īmān and conceal one’s unbelief. So the heretics (zanādiqah) are those who were referred to as hypocrites in the early part of Islām. They lived amongst the Muslims – and if an opportunity presented itself to them, they would make manifest their evil and would bare their teeth against the truth, just as occurs in our times right now.
“Know that there has never emerged a heresy except from the ignorant rabble who follow anyone who calls out wildly. They bend with every wind that blows…” These are the common folk, they tend to follow anyone who calls out, they don’t know which way they’re headed. As for the people of knowledge, the people who are firmly grounded, firm and steadfast upon knowledge, then they follow the truth. They are not deceived by large numbers and the large number of the people of evil. Allāh, the Most High High, said: “If you were to obey the majority of the people in the earth, they would cause you to stray from the Path of Allāh.” [Al-An’ām: 116] Consideration is given to those upon the truth even if they are small in number. Allāh, the Most High, said: “How many times has a small group of people overpowered a large group by Allāh’s permission – and Allāh is with the patient.” [Al-Baqarah: 249].
“So anyone who is like that has no religion…” The one who keeps changing from one side to another [in his belief] has no religion, so he is a hypocrite. Allāh, the Most High, said: “They switch between this side and that [in their belief] belonging neither to these nor to those – and he whom Allāh sends astray, you cannot find for him a way [to the truth].” [An-Nisā: 143] So this one who switches [between beliefs] has no religion.
“Allāh, the Mighty and Majestic said: «They did not differ until after the knowledge came to them [and then they differed] through envy among themselves.»…” So if they differed based upon ignorance it would be less of a calamity – but they differed whilst knowing [the truth]. This was due to them following their desires, so they differed. And had they followed the truth, they would have been in agreement and been united. Allāh the Most High, said: “And hold fast altogether to the Rope of Allāh and do not be divided…” [Āli ‛Imrān: 103] So if the opposition to the truth came about through ignorance then there is a hope that it will pass. However, if the opposition is upon knowledge, after knowing the truth then it is very hard for that to go away. That is because Allāh, the Majestic and Most High, said: “And who is more astray than the one who follows his desires without guidance from Allāh.” [Al-Qasas: 50] There is none more astray than this type of person. Allāh, the Most High, stated: “They did not differ until after the knowledge came to them [and then they differed] through envy among themselves.” This refers to the Children of Isrā’eel. They did not differ due to ignorance [of the truth], rather they differed between themselves due to the following of desires – and likewise is the case with those who resemble them from this Ummah.”
It-hāf al-Qāree, 2/38-40
This statement of Imām Al-Barbahāree should be a great lesson to the general folk and the beginner in seeking knowledge that he must remain steadfast upon the Sunnah and steadfast upon the truth regardless of the opposition he faces, and regardless of the great numbers who oppose the truth. He cannot allow himself to be diverted by every and any caller who calls out to him. The trait of the rabble is that have no firm stances; they bend with every gust of wind that blows. So from whichever direction they are called from, they bend in that direction. And this type of mindset causes a person to be constantly changing from one belief to another, from one manhaj to another, from one sect to another – he falls into a state of confusion and bewilderment, not knowing truth from falsehood. So he ends up supporting and aiding falsehood thinking it to be the truth and waging war against the truth thinking it to be falsehood. So the words of the scholars above should emphasise to us the importance of recognising the truth, learning it and holding fast to it; that one must not be led astray by the following of innovations and its people. Destruction lies in opposing the truth – opposition is either due to ignorance which is without doubt calamitous but what is worse is opposition after knowing the truth by following the misguided calls of the people of innovation and desires. These are the people of differing and separation who have torn apart the Ummah into sects and parties. So upon each person is cling to the Jamā’ah and they are Sahābah and those who followed them in each age from the scholars. And we ask Allah for safety and steadfastness.