Sources of authority: Quran and Sunnah
Islamic Studies · GCSE · The School
The Quran: primary and unmediated
Muslims hold the Quran to be the direct word of Allah, given through the angel Jibril to the Prophet ﷺ. Nothing sits between the words and their source. Muslims also hold that its text has been preserved unchanged. The Quran states this claim about itself: "We have sent down the Quran Ourself, and We Ourself will guard it" (15:9). This is why the Quran outranks every other source. It is checked against nothing else, and everything else is checked against it.
The Sunnah: secondary, but commanded
The Sunnah is the Prophet's ﷺ recorded example: what he said, did and approved. Its authority is not independent of the Quran. It rests on the Quran's own instruction. Believers are told to obey Allah and the Messenger (4:59), and the Messenger is described as an excellent model (33:21). So the Sunnah's status is not a rival claim beside the Quran. It is a claim the Quran itself makes.
How the two work together
The Quran often states a principle without the detail. The Sunnah supplies the detail. The Quran commands prayer; the Sunnah shows how many times a day, and how each prayer is performed. The Quran commands zakat; the Sunnah sets the threshold and the rate. Scholars name three relationships: the Sunnah CONFIRMS what the Quran already says, EXPLAINS how to carry it out, or, more rarely, ADDS a ruling the Quran does not state directly.
The Quran commands prayer in general terms, dozens of times. It does not state the number of daily prayers or their exact form. It is the Sunnah that fixes this. The Prophet's ﷺ own practice, and his instruction to "pray as you have seen me pray", set the number at five, with the specific movements and words used today. Take away the Sunnah, and a believer would know prayer is commanded but not how to perform it. This is the confirms-and-explains relationship in one example: the Quran commands, the Sunnah shows.
Checking a claim against both
A claim made "in the name of Islam" is checked against both sources, not either alone. A practice with no basis in the Quran or an authenticated hadith is not treated as binding, however old or widespread it has become. This is also why the hadith-grading discipline matters here. Only an authenticated report can function as a source at all. A weak or fabricated report has no more claim on a Muslim's practice than a personal opinion does.
Where the two sources leave room for difference
Not every question has a single answer written directly in either source. Where the text is silent, or open to more than one reading, scholars reason from it using established methods. Different schools of law have reached different conclusions in good faith. This is a difference of interpretation, not a disagreement about which sources count. Every school still answers to the same Quran and Sunnah.