Islam has various sources that are commonly accepted as evidence. These sources are classified in accordance to their role in understanding Divine laws and deriving supplementary laws that comply with Islamic fiqh (jurisprudence). However, Islam Stack Exchange is a question-and-answer website, not a fatwa website. As such, answers in Islam Stack Exchange are expected to be more similar to review than to research.
When answering questions, users are expected to present evidence that comes from authoritative sources and supports their assertion. There are two types of evidence that may be used:
- Primary evidence that provides direct proof of one's assertion
- Secondary evidence that supports or is consistent with primary evidence but may not constitute proof when viewed in isolation.
For each category of evidence presented below, examples of accepted references are listed. These lists are not meant to be conclusive or to be perceived as the only accepted authoritative sources; rather, these lists are what may be typically used in Islamic academia.
The Qur'an is the literal word of Allah ﷻ revealed to the Prophet ﷺ through His archangel Jibrīl. The ayāt (verses) of the Qur'an constitute, along with authentic hadiths, the highest level of evidence on all Islamic topics.
Stack Exchange is nonetheless an English site, which means that all references to the Qur'an must use an approved English translation of its meaning, and mention the surah (chapter) by name or number and the ayah by number as a minimum. For example:
[47:24] Then do they not reflect upon the Qur'an, or are there locks upon [their] hearts?
There are several approved English translations of the meaning of the Qur'an that can be used. The most common ones are Muhammad M. Pickthall, Muhsin Khan, Sahih International, and Yusuf Ali.
For completeness, a link to an online Qur'an translation may be provided. A number of websites have an approved translation (e.g., Al-Qur'an al-Kareem, Corpus, Islam Awakened, Muflihun Noble Quran, Noble Qur'an, and Tanzil Quran Navigator). The Arabic text may also be added — since the Qur'an was revealed in Arabic and translation may not always capture the fullness of the verse — but it is not a requirement, for example:
أَفَلَا يَتَدَبَّرُونَ الْقُرْآنَ أَمْ عَلَىٰ قُلُوبٍ أَقْفَالُهَا
Then do they not reflect upon the Qur'an, or are there locks upon [their] hearts?
Surat Muhammad, 47:24, Sahih International
Interpretations may not fully capture the meaning that the ayāt in Arabic convey. On most occasions, it adds value to provide text from an approved tafsīr (exegesis) to clarify the meaning, the context, or the reason of revelation of the ayah. Evidence may not always speak for itself. Only a limited set of tafsīr books are available in English, e.g., Tafsīr Ibn Kathir, Tafsīr Al-Jalalayn, and Tanwir al-Miqbās (see Al-Tafsir or QuranX). When required, references to other books of tafsīr in Arabic (e.g., Tafsīr as-Sa'di, Tafsīr al-Qurtubi, Tafsīr ash-Shanqīti, etc.) may be used provided an English translation is provided by the poster (the book Mu'jam Lughat al-Fuqahā' can be used to translate Arabic words to English).
The Sunnah of the Prophet ﷺ and the rightly-guided caliphs forms the second main source of primary evidence. Sunnah refers to the words said, actions performed, or acknowledgments through tacit consent by the Prophet ﷺ as documented in sahih (authentic) hadiths. Since Islam Stack Exchange is not a site for scholarly debates or original research, the Sunnah of the companions of the Prophet ﷺ also constitutes evidence when documented through authentic sources, and when it does not contradict a verse of the Qur'an or the Sunnah of the Prophet ﷺ. For discussions on manners, virtues, and other matters nor directly related to creed or jurisprudence, a hadith that is graded hassan (good) may be used as a primary evidence.
There are several books that document hadiths. There is no list of approved books as such, but the ones most commonly referred to are:
In addition, there is no list of approved English translation of the hadiths, so the poster has to either link to a website that provides a translation (e.g., Sunnah, Hadith Collection, Muflihun, and QuranX) or provide their own translation and mark it as such (the book Mu'jam Lughat al-Fuqahā' can be used to translate Arabic words to English).
Interpreting the hadiths may not fully capture the meaning of the text in Arabic. Occasionally, it adds value to provide an explanation or support or a study of the chain of narration of a hadith as evidence may not always speak for itself. Examples of such references are:
- At-Taqyīd wa al-Īdāh by Ibn As-Salāh
- Bulūgh al-Marām by by Ibn Hajar al-'Asqalāni
- Fat'h al-Bāri Sharh Sahīh al-Bukhāri by Ibn Hajar al-'Asqalāni
- Jāmi' bayna al-Hadeeth wa al-Fiqh by As-San'āni
- Nayl al-Awtār Sharh Muntaqā al-Akhbār by Ash-Shawkāni
- Nukhbat al-Fikr by by Ibn Hajar al-'Asqalāni
- Sharh an-Nawawi 'ala Sahih Muslim by An-Nawawi
- Subul as-Salām Sharh Bulūgh al-Marām by As-San'āni
- 'Umdat al-Ahkām by Al-Maqdisi
Fiqh (jurisprudence) is not necessarily a direct revelation from Allah ﷻ to the Prophet ﷺ; rather, it is mainly the understanding of Islamic laws, ibādāh (servitude or religious rituals), and practices based on Divine revelations. Islamic mujtahids (jurists) derive their understanding based on a rigorous methodology of ijtihad based on usūl al-fiqh (principles of jurisprudence). As such, their works are considered primary evidence.
There are four major schools of jurisprudence: Hanafi, Shāfi'i, Maliki, and Hanbali. Any of the major books of any of these four schools or books on usūl al-fiqh counts as a primary evidence. For example:
- Ad-Durr al-Mukhtār by Ibn 'Ābidīn
- Al-Ashbāh wa an-Nadhā'ir by As-Subki
- Al-Iqnā' by Ibn a-Mundhir
- Al-Mughni by Ibn Qudāmah
- Al-Muhalla by Ibn Hazm
- Al-Umm by Ash-Shāfi'i
- Al-Usūl min 'Ilm al-Usūl by Muhammad ibn al Uthaymeen
- At-Tadhkira by Ibn al-Mulaqqin
- Bidayat al-Mujathid by Ibn Rushd
- Rawdat an-Nādhir by Ibn Qudāmah
- Rawdat at-Tālibīn by An-Nawawi
- Sharh al-'Umdah by Ibn Taymiyyah
- Sharh az-Zurqāni by Ahmad az-Zurqāni
- Shifā' al-Ghalīl by Ibn Ghazi al-Miknasi
- Tuhfat al-Muhtāj by Ibn Hajar al-Haytami
- 'Umdat al-Ahkām by Al-Maqdisi
- 'Umdat al-Fiqh by Ibn Qudāmah
- Zād al-Mustaqni' fi Ikhtisār al-Muqni' by Al-Hajjawi
Topics normally covered under 'aqīda (creed) are tawhīd (monotheism or the oneness of Allah), bid'ah (innovation in religion), al-asmā' wa as-sifāt (names and attributes of Allah), imān (faith, mainly around the six articles of faith), and shubuhāt (heresies or misconceptions).
There are numerous books that discuss Islamic creed based on evidence from the Qur'an and the Sunnah, for example:
- Al-'Aqīda al-Wāsitiyyah by Ibn Taymiyyah
- Al-I'tisām by Ash-Shātibi
- Al-Imān by Ibn Taymiyyah
- At-Tawhīd by Abu Mansur al-Maturīdi
- At-Tawhīd by Ibn Khuzaymah
- At-Tawhīd by Ibn Taymiyyah
- At-Tawhīd by Mohammad by Mohammad 'Abdu
- At-Tawhīd by Mohammad ibn 'Abdul-Wahhāb
- Kashf as-Shubuhāt by Mohammad ibn 'Abdul-Wahhāb
- Ma'ālim Usūl ad-Dīn by Fakhr al-Din al-Razi
- Matn at-Tahhaawiyyah by At-Tahhaawi
- Thalāthat al-Usūl by Mohammad ibn 'Abdul-Wahhāb
- Usūl al-Imān by Mohammad ibn 'Abdul-Wahhāb
- Al-Qawā'id al-Arba'ah by Mohammad ibn 'Abdul-Wahhāb
Since, however, such books are often misquoted or misuderstood by the layman Muslim, when referencing such books, it is important to quote the relevant parts (and provide an English translation when no English version is available — the book Mu'jam Lughat al-Fuqahā' can be used to translate Arabic words to English) for the source to count as a primary evidence.
Companions' and Scholars' views
It is a common rule that scholarly teachings are to be "evidenced for, not by" (Arabic: أقوال العلماء يحتج لها لا بها). This is indeed the case when pursuing laws of jurisprudence by highly-esteemed scholars.
In Majmū' al-Fatāwa by Ibn Taymiyyah 27/281, 'Abdullah ibn 'Umar emphasized this rule to some of the companions who misunderstood a teaching by his father, 'Umar ibn al-Khattāb, that the Prophet ﷺ was the only person whose teachings are to be taken verbatim, but all others (companions included) may err. The same concept was expressed by all scholars of jurisprudence, e.g., in Mukhtassar Khilāfāt al-Bayhaqi 2/70, Ash-Shāfi'i is quoted telling his students that any contradictions in his books to the Sunnah of the Prophet ﷺ are to be abandoned.
Having said that, in an ostensibly anonymous environment like Islam Stack Exchange, the posters of questions or answers are not at the scholarly level to critique teachings of the companions or highly-esteemed scholars. Even if one may assume that some users may have the required level of knowledge, the anonymity of and by itself renders all users here as followers rather than scholars. For followers, the teachings of the companions and highly-esteemed scholars, when documented in authoritative text, constitute primary evidence.
Customs and traditions
Customs and traditions of a society at any level do not constitute evidence unless endorsed through primary evidence. Practices of the companions of the Prophet ﷺ that are not based on primary evidence only constitute evidence when further supported by jurisprudential endorsement that said practices may be treated as such.
Books of sīrah (biography of the Prophet ﷺ, e.g., Zad al-Ma'ād by Ibn Qayyim al-Jawziyya) count only as secondary evidence unless supplemented by an ayah in the Qur'an or a sahih or hassan hadith. Books of tarājim (biographies of companions or following generations or scholars, e.g., Rawdat al-'Uqalaa by Ibn Hibbān al-Busti or Siyar A'lām an-Nubalā' by Adh-Dhahabi) may be likewise perceived except when responding to questions about the authenticity of a hadith.
Stack Exchange and other sites
Answers on Stack Exchange or other similar sites may be referenced as evidence only when said content provides primary evidence to support their view. An answer referencing such content must quote only the relevant portions on said websites and provide a full reference to the content (name of the author, link to the content, year of publication, etc.) when available.
While the Qur'an supersedes all previous scripture, the teachings in previous scripture may be used as supporting evidence when enforced through the Qur'an or authentic hadiths (e.g., fasting as in Qur'an 2:183). Non-Islamic scripture does not constitute evidence of and by itself as it may contain unverified stories from the Children of Israel or it may be abrogated by Islamic scripture.
Nonevidence is any material that does not have evidentiary value nor supplementary value to primary or secondary evidence. All types of anecdotal evidence — including but not limited to personal experiences or dreams or similar references — are nonevidence except when referenced through the Qur'an or the Sunnah solely.
The content of this answer is based on multiple sources: