Sharia is presented in the West, by Muslims, and even by some useful idiots, as if it were simply the Islamic equivalent of Jewish religious law or Christian canon law: a private religious framework governing prayer, fasting, marriage, diet, and personal morality.
That description is false.
Sharia is a total legal and moral order. It does not recognize any division between mosque and state, private faith and public law, worship and government. It reaches into prayer, food, clothing, commerce, marriage, divorce, inheritance, testimony, criminal punishment, war, taxation, relations with non-Muslims, the structure of government, and the legitimacy of political authority.
It tells the Muslim what is obligatory, recommended, permitted, offensive, and forbidden. It tells the judge how to rule, the husband what rights he has over his wife, the ruler how to treat conquered non-Muslims, the army what to do with captives, and the state what to do with someone who leaves Islam.
The first thing a Westerner has to understand is that Sharia does not begin with the autonomous individual. It begins with the Lawgiver. In Islam, good and evil are not finally determined by unaided human reason. The standard is what Allah and Muhammad have commanded or forbidden. What the Lawgiver has indicated as good is good, what the Lawgiver has indicated as bad is bad, and reason is not the final measure.
A Western liberal order begins with the individual human being possessing rights that precede the government, the state is limited, law is supposed to protect citizens equally, religion can persuade, preach, organize, worship, and argue, but it does not possess the sword of the state simply because it claims divine authority.
Sharia thinks in a different direction. The law is already given, the question is not whether the citizen consents to it, but how the divine ruling applies to him. Human acts are classified legally as obligatory, recommended, permissible, offensive, or unlawful. Sharia, therefore, is not simply a collection of devotional suggestions; it is an architecture of duties and prohibitions in which violation can carry consequences in this world as well as the next.
That is why reducing Sharia to the hijab, halal food, or five daily prayers is absurd. Those things are part of it, but so are jihad, apostasy, jizya, the caliphate, amputation, stoning, unequal legal status between Muslim and non-Muslim, male guardianship in marriage, and a political order whose purpose is explicitly to uphold the religion.
When it comes to what Sharia actually contains, Islam is remarkably monolithic.
Sharia governs worship, marriage, divorce, inheritance, commerce, criminal punishment, apostasy, jihad, the status of non-Muslims, and political authority. The disagreement is usually over how a rule is applied, not over whether these subjects belong to Islamic law in the first place.