One of the maladies of the heart is to hold a bid’at, which means to hold a heretical, wrong or aberrant belief. Most Muslims suffer from this disastrous malady. The reason which leads one into this malady is one’s attempt to rationalize or reason in the matters which cannot be sensed through sense organs and which cannot be reached or comprehended through calculations and believing in matters wherein reason errs and makes mistakes. Every Muslim should follow the teachings of either one of the two Madhhabs with respect to faith, i.e., “Mâturîdî” or “Ash’arî”. Following the teachings of any one of them will protect or save a person from the malady of heresies. For, in matters beyond the reach of mind, the scholars of (the medial and therefore the only correct path called) Ahl as-sunnat followed only the Qur’ân al-kerîm and hadîth-i-sherîfs, thus utilizing their mental capacities in delving into these two sources and trying to understand their meanings. They wrote, in their books, what they learned from the Ashâb-i-kirâm, who in turn had acquired their religious learnings from the Messenger of Allah.
A person will become a disbeliever if he denies or doubts about something which is taught clearly in the Qur’ân al-kerîm or in hadîth-i-sherîfs. Giving wrong meanings to commandments that are not taught clearly and are therefore doubtful would be “bid’at.” A person becomes an ahl al-bid’at if he believes in his wrong interpretation or understanding. However, if a person rejects the commandments by saying, for instance, “How could this happen! This could not be! My mind does not accept that!”, he will become a disbeliever. If a person asserts that a prohibited (harâm) thing is permissible (halâl) and if his statement is based on an âyat of the Qur’ân or on a hadîth, he does not become a disbeliever but he becomes an “ahl al-bid’at.” Stating that the election of hadrat Abû Bakr and Hadrat ’Umar to the post of Caliphate was not right constitutes a bid’at. On the other hand, going further and stating that they did not have rights to the post of Caliphate constitutes disbelief (kufr).
Muhammad Shihristânî ‘rahimahullâhu ta’âlâ’ says in his book Milal wa Nihal that the scholars of the Hanafî Madhhab followed the teachings of imâm Abû Mansûr al-Mâturîdî ‘rahimahullâhu ta’âlâ’ with respect to faith (i’tiqad). For, Abû Mansûr al-Mâturîdî applied the methodology (“usûl” and “furu”) of Imâm a’zam Abû Hanîfa ‘rahimahullâhu ta’âlâ’, the founder of the Hanafî Madhhab. “Usûl” means “i’tiqad” belief. “Furu” means “ahkâm-i-shar’iyya” or rules that are based on Islamic laws. The scholars of “Mâlikî”, “Shâfi’î” and “Hanbalî” Madhhabs followed the teachings of Imâm Abû Hasan al-Ash’arî ‘rahimahullâhu ta’âlâ’ with respect to faith (i’tiqad). Abû Hasan al-Ash’arî followed the “Shâfi’î” Madhhab. Imâm al-Subkî ‘rahimahullâhu ta’âlâ’ who was one of the famous “Shâfi’î” scholars said that he had studied the book of Abû Ja’far Tahâwî ‘rahimahullâhu ta’âlâ’ who was one of the scholars of the Hanafî Madhhab, and noticed that it was almost the same as the teachings of the “Ash’arî Madhhab in faith. They differed from each other only in three points. Abdulwahhâb Tâj-ud-dîn al-Subkî, who was the son of imâm abûl Hasan Alî Subkî ‘rahimahullâhu ta’âlâ’, said that he had studied the books of the scholars of “Hanafî” Madhhab in faith (i’tiqad) and noticed that they were in disagreement with “Shâfi’î” Madhhab in faith in thirteen points. But he said that their disagreements were on minor matters and that those differences did not mean that they had deviated from the correct path. They do not differ in essential matters. They both are in the correct (haqq) path. Muhammad Hadimî ‘rahimahullâhu ta’âlâ’ states in the three hundred and seventeenth page of his book Berîqa that he has studied the teachings of both ‘Mâturîdî and Ash’arî Madhhabs in credal matters and estimated that the discrepancies between the two Madhhabs, including the very minor differences, added up to seventy-three.
Every bid’at holder has inferred wrong meanings from âyats of Qur’ân al-kerîm and hadîth-i-sherîfs with covered meanings. Our Prophet ‘alaihis-salâm’ said, “He who gives a false interpretation to the Qur’ân according to his own mind, thought and knowledge, and who writes made up interpretations [those opposed to the interpretations which the great men of religion have prepared after learning them from our Prophet and from his Ashâb] is a kâfir.” We shouldn’t buy or read the false books of interpretations published to make money by those who know nothing of salât and îmân; we shouldn’t believe their decorated advertisements.
The valuable and right teachings derived from the Qur’ân al-kerîm and hadîth-i-sherîfs is only what the [Ahl-i Sunnat] savants understood and explained. Every renegade, every deviant, every man of bid’at, and every ignorant person supposes and claims that the way he follows is compatible with the Qur’ân al-kerîm and hadîth-i-sherîfs. For this reason, not every meaning derived from the Qur’ân and hadîths is to be accepted and esteemed.
 Ref: This paragraphes are quoted from the book “Ethics of Islam” page 36, which is the translation of the book Berîka written by Abû Sa’îd Muhammad bin MustafâHâdimî ‘rahima hullâhu ta’âlâ’, who passed away in 1176 Hijrî, 1762 A.D. in Konya / Turkey and the book Akhlâq-i-Alâî written in Turkish by Alî bin Amrullah ‘rahimahullâhu ta’âlâ,’ who passed away in 979 Hijrî, 1572 A.D. in Edirne / Turkey. You can find the whole book and the other valuable books in the web site www.hakikatkitabevi.com.tr and download in PDF format for Adobe Acrobat Reader, EPUB format for iPhone-iPad-Mac devices and MOBI format for Amazon Kindle device.