In The Name of Allaah, The Most Meciful, The Bestower of Mercy

Al-Allaamah Rabee Bin Haadee Al-Mad’khalee [may Allaah preserve him] said:

Every sect of ahlul bidah gathers between truth and falsehood; denies the truth that is with the other sect of bidah and believes in that which they possess of falsehood. Shaikhul Islaam Ibn Taymiyyah [may Allaah have mercy upon him] said: Allaah said: [ وَإِذَا قِيلَ لَهُمۡ ءَامِنُواْ بِمَآ أَنزَلَ ٱللَّهُ قَالُواْ نُؤۡمِنُ بِمَآ أُنزِلَ عَلَيۡنَا وَيَكۡفُرُونَ بِمَا وَرَآءَهُ ۥ وَهُوَ ٱلۡحَقُّ مُصَدِّقً۬ا لِّمَا مَعَهُمۡ – And when it is said to them (the Jews), “Believe in what Allah has sent down,” they say, “We believe in what was sent down to us.” And they disbelieve in that which came after it, while it is the truth confirming what is with them]. [Surah Al-Baqarah Aayah 91]

That is because they initiate an innovation in the religion, mix it with what the Messengers brought, split their religion and become sects; so there’s truth and falsehood within every group amongst them. They deny the truth that is with the other group and believe in the falsehood that is with them. This is the state of affairs of all the people of bidah, for indeed with them is truth and falsehood, so they split their religion and become sects. Every sect denies the truth that is with the other sect and believes in the falsehood that is with them, such as the Khawaarij and Shee’ah. These ones [i.e. khawaarij] deny the virtues that have been affirmed (established) for Ameerul Mumineen Ali Ibn Abee Taalib [may Allaah be pleased with him], believe in that which has been reported regarding the virtues of Abu Bakr and Umar [may Allaah be pleased with both of them], and they believe in that which they have innovated of Takfeer against Ali, those who ally with him and love him. And those ones [i.e. the Shee’ah] believe in that which has been transmitted regarding the virtues of Ali Ibn Abee Taalib and deny the virtues of AbuBakr and Umar, and then believe in that which they have innovated of Takfeer and evil speech regarding Abu Bakr, Umar and Uthmaan. (1)

Shaikhul Islaam Ibn Taymiyyah [may Allaah have mercy upon him] also said: The basis of the misguidance of these ones is their belief that the Imaams of guidance and the Jamaa’ah [i.e. the pious predecessors] have exited the (confines) of justice and are misguided. This is the view of those who have abandoned the Sunnah, such as the Raafidah and those similar to them. And that which they consider to be oppression, they hold that it is disbelief and then innovate rulings for it. These are the three stances – [i.e. they revile the pious predecessors, declare certain acts as oppression and then innovate rulings against them] – held by those who exit the Sunnah, such as the Harooriyyah [i.e. the Khawaarij], the raafidah [Shee’ah] and those similar to them. They isolate some of the fundamental principles of the Islamic Religion until they exit from it (completely), just like an arrow goes through a hunted game. (2)

Shaikhul Islaam Ibn Taymiyyah [may Allaah have mercy upon him] also said: The people of bidah, such as the khawaarij, they initiate an innovation [in the religion], excommunicate the one who opposes them and declare lawful the shedding of his blood. These people refute the bidah of each other, whilst he [i.e. the refuter] is also an innovator; so he refutes a bidah with another bidah, and falsehood with another falsehood. (3)

[Ref 1:Minhaaj As-Sunnah 5/168. Quoted by Shaikh Rabee in Al-Mukhtaaraat Al-Bahiyyah Min Kutub Shaikhil Islaam Ibn Taymiyyah. Pages 280-281, slightly paraphrased]

[Ref 2: Majmoo Al-Fataawaa 28/496]

[Ref 3: Majmoo Al-Fataawaa 16/96]