ما يُعلِّمه الإسلام
Islamic law is not a code somebody published. It is a body of reasoning built from the Quran and from graded reports about the Prophet, using an explicit method — which texts count, how a general command relates to a specific one, what to do when reports conflict, how much weight local custom carries. Different scholars settled that method differently, early, and the resulting traditions are the schools of law. Among Sunni Muslims four survive: Hanafi, Maliki, Shafi'i and Hanbali. Twelver Shia follow the Ja'fari school; Zaydi and Ismaili Shia and the Ibadis of Oman have their own. Disagreement between them has been treated as legitimate breadth for most of Islamic history, not as one school being heretical.
ما قد تلاحظه
Two Muslims praying slightly differently beside each other and neither minding. Muslims in the same city disagreeing about when Ramadan starts. Someone saying 'in my school' or 'my family follows' — which is a real answer, not evasion. And occasionally the opposite: people who treat a difference of school as a difference of religion, which is a modern development and a minority one.
لماذا يهم
Because 'Islam says' is usually the wrong shape of sentence. For a small core there is no disagreement at all: one God, the five daily prayers, Ramadan, the prohibition of pork and alcohol. Outside that core, an accurate answer often has to name a position and whose it is. Any source that gives you one confident ruling on a contested question, without saying it is contested, is telling you less than it appears to.
ما يختلف
Almost everything in the detail: the exact times of the afternoon prayer, whether the hands are held at the chest or below the navel, what invalidates a fast, whether a particular food additive is permitted, how a marriage contract is concluded. Which school predominates differs by region for historical reasons, and it is a matter of where a tradition spread rather than of nationality. This platform never assumes yours from your country: the calculation and jurisprudence settings are suggestions with a recorded source, and you can change any of them.
مفهوم خاطئ شائع
That the Sunni–Shia split is about doctrine in the way Catholic and Protestant is. It began as a dispute about legitimate authority after the Prophet's death and developed theological consequences over centuries. A second misconception is that Sufism is a sect. It is a tradition of inward discipline found within Sunni and Shia Islam; a Sufi is usually also a Hanafi or a Shafi'i or a Ja'fari.
اسأل أكثر
If you want to know what a particular Muslim actually holds, the useful question is not 'what does Islam say' but 'what do you follow, and why'. Most people are pleased to be asked it that way.