How Islamic law is derived: Qur'an, Sunnah, ijma' and qiyas

Islamic law is derived from four sources, in a fixed order of authority: the Qur'an; the Sunnah of the Prophet ﷺ; ijmaʿ, the consensus of qualified scholars; and qiyas, reasoning by analogy from a case the texts settle to one they do not. All four Sunni schools accept all four, in that order. The discipline that governs how they are used is usul al-fiqh — legal method — and it is built to accommodate disagreement between qualified people rather than to eliminate it: a judge who reasons and errs is still rewarded for the reasoning. In Canada none of this has legal force; it binds a Muslim as personal religious obligation, and it is Canadian law that governs.

The four agreed sources, in order

All four Sunni schools work from the same four usul — sources — in the same order of authority. The order is not arbitrary: each step is only reached because the one above it has not settled the question.

1. The Qur'an. The revealed text, and the first place a jurist looks. Only a small fraction of its verses are legal in content; on inheritance it is unusually specific, setting out named fractions for named heirs in Surah an-Nisa 4:11, 4:12 and 4:176.
2. The Sunnah. The Prophet's ﷺ words, acts and endorsements, transmitted as hadith and graded for reliability by an entire discipline built for the purpose. The Sunnah specifies what the Qur'an states generally — the Qur'an commands prayer; the Sunnah sets out how it is performed.
3. Ijmaʿ — consensus. The agreement of the qualified scholars of a generation on a ruling. Where it is established, the question is treated as closed.
4. Qiyas — analogy. Extending a ruling from a case the texts address to one they do not, on the strength of the reason the first ruling exists.

How the sources were assembled into a method

The discipline that studies this is usul al-fiqh — literally the roots of the law, as against fiqh itself, the branches. Al-Shafiʿi's al-Risala is traditionally credited as the first systematic treatment of it, which is why the Shafiʿi school is associated with legal method in a way the others are not. That traditional account is contested in the academic literature: Wael Hallaq argued in 1993 that usul al-fiqh emerged as a discipline only in the late ninth and early tenth centuries, after the arguments about the sources had already been won, and the article set off a long controversy in which other scholars defended earlier origins. The dating is disputed; the content of the method is not.

The most-quoted single account of the method is the report of Muʿadh ibn Jabal, sent to Yemen as a judge and asked how he would decide: by the Book of God, then by the Sunnah of His Messenger, then by his own reasoned effort. It appears in Sunan Abi Dawud 3592. It deserves a caveat that popular retellings usually omit: hadith critics have long faulted its chain — it runs through al-Harith ibn ʿAmr and unnamed “men from among the companions of Muʿadh” — and al-Albani placed it in his collection of weak reports. Jurists nonetheless treated it as an accurate description of the method, which is a fair summary of its standing: influential as a statement of practice, weak as a chain of transmission.

The consensus principle rests on firmer textual ground: the report that the community will not agree upon an error, in Sunan Ibn Majah 3950 and at Jamiʿ at-Tirmidhi 2167, where al-Albani graded it hasan, together with Surah an-Nisa 4:115 on following other than the way of the believers. Even so, the classical scholars were cautious about claiming it. Ahmad ibn Hanbal is reported to have said that whoever claims consensus is a liar — a remark Ibn Taymiyya read as directed at claims of consensus after the earliest generations, on the practical ground that no one could canvass the scholars of a whole world and know.

Qiyas has a defined structure, and knowing it is what separates analogy from guesswork. There is the case the text rules on (asl), the new case (farʿ), the ruling to be extended (hukm), and — the load-bearing element — the effective cause (ʿilla) the jurist identifies as the reason for the original ruling. The textbook illustration: the Qur'an prohibits khamr at Surah al-Ma'idah 5:90; the jurists identified the ʿilla as intoxication rather than the particular substance; the prohibition therefore extends to any intoxicant. Two qualified jurists can agree on every text and still differ on the ʿilla — and then their rulings differ, legitimately. Not every school accepted analogy at all: the Zahiri jurists, Ibn Hazm foremost, rejected qiyas as a source outright.

Ijtihad, taqlid, and what a fatwa actually is

Ijtihad is the disciplined effort of a qualified jurist to derive a ruling from the sources. The qualifications the classical writers set were demanding — command of Arabic, of the Qur'an and its legal verses, of the hadith corpus and its grading, of the points on which consensus is claimed, and of the method itself — and the maxim lā ijtihāda maʿa al-naṣṣ, no ijtihad in the face of an explicit text, marks the outer boundary: where a text settles a matter, there is nothing to exert reasoning about.

Taqlid is the other side of it: a non-specialist following a qualified scholar's ruling without deriving it himself. This is the normal position for almost everyone, and the Qur'an frames it plainly at Surah an-Nahl 16:43 — ask the people of knowledge if you do not know. It is not intellectual surrender; it is the same thing a patient does with a physician.

A fatwa is a scholar's answer to a question put to him. Three things follow from that definition, and all three are routinely lost in public discussion. It is an answer to a question, so it is shaped by the facts the questioner gave and does not automatically transfer to anyone else's facts. It is advisory: a fatwa binds nobody — the classical distinction is between a fatwa and a qadaʾ, a judge's ruling, which does bind the parties before him. And it is attributable: a fatwa comes from a named scholar reasoning within a named school, which is why “there is a fatwa saying…” conveys almost nothing until you know whose, on what facts, in which school.

Fatawa also change, legitimately, and the tradition says so explicitly. Ibn al-Qayyim devoted a section of Iʿlam al-Muwaqqiʿin to the principle that a fatwa changes with the change of times, places, customs and circumstances — which is exactly why a ruling given about a transaction in fourteenth-century Damascus may not answer a question about a Canadian registered account. Those are ijtihad questions, not settled ones.

Why qualified disagreement is built in

The clearest statement of the tradition's own attitude is a hadith about judging, in Sahih al-Bukhari 7352 and Sahih Muslim 1716: a judge who exerts his reasoning and gets it right has two rewards, and one who exerts his reasoning and gets it wrong still has one. Read it slowly. It presumes that a qualified person acting properly can reach the wrong answer, it attaches no blame when that happens, and it rewards the effort itself. A system that expected uniform outcomes could not have said that.

There is an incident to match it. Returning from the campaign of the Trench, the Prophet ﷺ told the Companions that none should pray ʿAsr except at Banu Qurayza. The prayer time fell while they were still on the road. Some prayed on the way, reasoning that speed had been the point; others held off and prayed on arrival, taking the instruction literally. When it was put to him, as Sahih al-Bukhari 946 records, he blamed neither group. Two readings of one instruction, both accepted.

So ikhtilaf is not the residue of an argument nobody won. It is the expected output of a method that lets qualified people reason from shared texts about cases those texts do not decide. The schools are what happens when that reasoning is done consistently, recorded, taught and refined over generations — and where all four converge, as they do across most of inheritance law, that agreement is itself strong evidence rather than coincidence.

How much of that touches an ordinary family is a fair question, and the honest answer is: less than people expect, but not nothing. The four schools agree on the Qur'anic fractions, the one-third bequest ceiling, the order in which an estate pays out, and proportional abatement; they differ in a small number of well-mapped configurations. Whether it matters which madhhab you follow when drafting a will depends entirely on which relatives survive you — and what to do when a family follows different schools is a question we get often enough to have answered separately.

Where the schools differ

On the four agreed sources there is no dispute: all four schools accept the Qur'an, the Sunnah, ijmaʿ and qiyas, in that order. The differences begin one step further out, among the additional principles each school admits when the four run out — and because those principles govern method rather than any single rule, they are the deepest reason the schools' outputs differ at all.

The Canadian legal position

Canadian law has its own sources, and no Islamic one is among them. Legislative authority is divided between Parliament and the provincial legislatures by the Constitution Act, 1867; courts apply statute and the common law, bound by the decisions of higher courts; and everything is subject to the Constitution, including the Canadian Charter of Rights and Freedoms. A fatwa, a scholarly consensus and a school's settled position have exactly the same standing in a Canadian courtroom as any other statement of religious belief: they are not law, and no judge is obliged — or permitted — to apply them as law.

Nor will a Canadian court decide which scholar is right. That is the holding of Syndicat Northcrest v. Amselem, 2004 SCC 47: at para. 50 the Supreme Court said that “the State is in no position to be, nor should it become, the arbiter of religious dogma”, and at para. 51 that a court “is not qualified to rule on the validity or veracity of any given religious practice or belief, or to choose among various interpretations of belief”, though it may inquire into a claimant's sincerity where sincerity is genuinely in issue. A judge asked to determine what Islamic law requires will decline — and that is a feature of the constitutional arrangement, not a gap in it.

The consequence for anyone hoping a Canadian body might resolve a fiqh dispute authoritatively is that none will. Ontario closed the nearest thing to a route in 2006: “family arbitration” is now defined in the Arbitration Act, 1991 as arbitration conducted “exclusively in accordance with the law of Ontario or of another Canadian jurisdiction”, and s. 2.2 provides that where a family matter is decided in a process not so conducted, “the process is not a family arbitration” and “the decision is not a family arbitration award and has no legal effect”. Religious advice remains entirely lawful to seek and to follow; it simply has no civil force. The chronology is on the 2003–2006 Ontario page.

Where they meet

What this leaves is a division of labour, and it is a workable one. A scholar's job is to tell you what the ruling is for your facts and your school. A Canadian lawyer's job is to put that outcome into an instrument the province will enforce. Neither can do the other's work: a religiously sound answer expressed in vague drafting fails in probate, and a beautifully drafted will distributing the wrong way fails on its own terms.

That is why the order of operations matters. Establish the configuration first — who survives you, and what each takes under the school you follow. Our inheritance calculator asks which school you follow before anything else, because in a handful of family configurations the answer changes; the worked case studies show what those configurations look like in real families. Then have the fractions drafted into a will that satisfies your province's formalities.

And when you take a question to a scholar, give it the shape a fatwa needs. Say which school you follow, set out the facts completely — including the Canadian ones, since a jointly held house and a designated registered account behave differently from anything in the classical books — and ask about your situation rather than about the general rule. A fatwa is an answer to a question; a vague question gets an answer that will not fit.