Sources of Islamic legislation
A brief introduction to the meaning of Islamic jurisprudence (fiqh), its principles, and The Leading Fiqh Scholars such as Abu Hanifah, Malik, Al-Shafi'i and Ahmad ibn Hanbal. It includes all the practical rules that every Muslim, man or woman, should know, citing their bases in the Qur’an and the Sunnah in an easy and simple way.
Sources of Islamic legislation
One: Textual sources
1-The Qur’an. It embodies the Islamic faith and the revelation that explains the faith Allah wants all people, in all ages, to adopt. It is indeed the first resort to which a scholar must refer when considering a ruling on any question. It is equally applicable to all people in all generations. Allah commands people to follow and implement His rulings of permission and prohibition outlined in the Qur’an.
‘Follow, [O mankind], what has been revealed to you from your Lord, and do not follow other than Him any allies.’
2-The Sunnah. This is the second source of Islamic legislation, ranking next to the Qur’an. It is defined as ‘everything authentically reported to have been said, done or approved by the Prophet (peace be upon him)’. Scholars are unanimous that the Sunnah is binding and serves as a source of legislation. It is unanimously agreed that the Sunnah must be implemented provided that its authenticity is established and it is not exclusive to the Prophet (peace be upon him) himself. Its verdicts of permissibility and prohibition are equally valid as the Quran.
Two: Sources requiring scholarly endeavour (i.e. ijtihad)
1-Unanimity (i.e. Ijma'): This means the consensus by all scholars who are qualified to exercise ijtihad, i.e. scholarly endeavour, in any particular period after the era of Prophethood, to arrive at a practical ruling.
2- Analogy (i.e. Qiyas): This means applying the ruling specified by a religious text on a certain matter to another matter for which no text refers, provided that the same reasoning applies to both of them. 
3-Subtle analogy (i.e. Istihsan): Discarding the verdict of a clear analogy in preference of a subtle one, or discarding a universal verdict in preference of a peculiar one, provided that such a process is based on firm evidence.
4- Interests without rulings (i.e. Masalih Mursalah): This refers to matters that bring benefit to people but there is no religious evidence that approves or disapproves of them. Nor are there cases to which they may be compared in order to arrive at rulings concerning them through analogy. However, a ruling on such a matter is important because it brings some benefit or prevents some harm, which is the ultimate aim of Islamic law.
5- Customs of Muslims (i.e. al- 'Urf): This refers to what people traditionally do or say and is not contrary to any religious text. Tradition and habit, which means something repeatedly done, signify the same thing, and they apply to speech and deeds.
6- Statements by the Prophet’s (peace be upon him) Companions’: A statement by a Companion of the Prophet (peace be upon him) relating to something that cannot be determined by reasoning or research, such as essential religious matters and worship practices, is accepted as valid. It is considered to have been learnt directly from the Prophet (peace be upon him). Hence, scholars consider such a statement as a hadith with a chain of transmission going up to the Prophet’s (peace be upon him) Companion, without being expressly attributed to the Prophet(peace be upon him). As such, it is part of the Sunnah, although it appears to be a Companion’s view.
7- The laws of earlier divine religions: This refers to legislation given by Allah to past communities through their own Prophets (peace be upon them all). Muslim scholars have studied such laws and whether they apply to us or not.
8- Prevention of what leads to the prohibited (i.e. sadd al-dhara’i'): This aims to prohibit any means that leads to something forbidden that involves harm. According to scholars of Fiqh methodology dhara’i' means whatever is done in order to facilitate doing something forbidden that involves causing harm. What facilitates something forbidden is forbidden, just like what facilitates something obligatory is obligatory. 
9- Al-Istishab: This means giving something its original ruling, as it was recognized, unless there is evidence confirming that this original ruling has been subject to change. Alternatively, it may be defined as considering the original ruling continuing for the present and the future until something appears to change it based on evidence. In essence, what was established in the past should normally remain valid for the future.
- Al-Shawkani, Irshad al-Fuhul, p. 71; Ibn Qudamah, Rawdat al-Nazir, p. 67.
- Al-Shawkani, ibid., p. 198.
- Al-Shafi'i, Al-Risalah, p. 505; Abu Ya’la, Al-'Uddah fi Usul al-Fiqh, vol. 4, p. 1,394; al-Razi, Al-Mahsul, vol. 6, p. 1,215.
- Al-Amidi, Al-Ihkam, vol. 4, p. 216; al-Shawkani, Irshad al-Fuhul, p. 218.
- A.F. Abi Sinnah, Al- 'Urf wal- 'Adah fi Ra’y al-Fuqaha’, p. 8.
- Al-Amidi, Al-Ihkam, vol. 3, p. 195.
- Al-Juwayni, Al-Talkhis, vol. 2, p. 266; al-Sarakhsi, Al-Usul, vol. 2, p. 99; Abu al-Khattab, Al-Tamhid, vol. 2, p. 417.
- Ibn Hazm, Al-Ihkam, vol. 2, p.180; al-Zarkashi, Al-Bahr al-Muhit, vol. 8, p. 89; Ibn 'Abd al-Salam, Qawa'id al-Ahkam, p. 182; Ibn al-Qayyim, I'lam al-Muwaqqi'in, vol. 3, p. 121; Ibn al-Subki, Al-Ashbah wal-Naza’ir, vol. 1, p. 119.
- Al-Shawkani, Irshad al-Fuhul, p. 237.