A senior Taliban commander declared on Wednesday that the return of Taliban rule in Afghanistan will mean a return to sharia law, the group’s interpretation of Islamic religious law, after the Islamist militant group swept the country, deposing the US-backed government.

The takeover has sparked concern and speculation about Afghanistan’s future.

Sharia is an Arabic word that means “the way” or “the clear, well-trodden path to water.” In practice, it is understood, interpreted, and applied differently in different parts of the world, depending on different traditions, cultural contexts, and the role of Islam in government. It is a set of religious rules that Muslims follow to guide their daily lives, including prayer and fasting. It is based primarily on the Koran, Islam’s holy book, as well as the words and teachings of the prophet Muhammad.

Leaders, clerics, and practitioners approach the traditions and precedents in a variety of ways.

Sharia could play a role in criminal law — a strict code of punishment used in only a few countries — or Islamic personal law, which governs issues such as marriage, inheritance, and child custody and is more common throughout the Muslim world. When the Taliban ruled the country from 1996 to 2001, they imposed a strict interpretation of Sharia law. Women were forced to wear burqas (head-to-toe, face-covering garments) and faced beatings if they went outside without a male guardian.

Girls’ schools were closed. People who broke the Taliban’s rules faced public execution, whipping, or stoning.

Over the last two decades, some parts of Afghanistan have remained or returned to Taliban control. In those areas, the group maintained strict rule despite some modest signs of reform. Despite some attempts to strike a conciliatory tone, the history of the Taliban’s extremist rule means that many people remain fearful.

The commander, Hashimi, said that the rights of Afghan women would be decided by a council of Islamic scholars. He outlined a system that is strikingly similar to the Taliban’s previous regime.

The Taliban’s spokesman, Zabihullah Mujahid, told reporters earlier this week that the Taliban would respect women’s rights within the framework of Islamic law, but he didn’t elaborate. He also made a hazy promise to protect press freedoms if journalists did not work “against national values.”

Abdulaziz Sachedina, a religion and politics professor at George Mason University who specializes in Islamic studies, believes the Taliban will need time and effort to implement sharia law policies.

Sharia law, according to Sachedina, does not provide codified systems for the modern nation-state, such as commercial and administrative laws. “There is nothing in Sharia that says, this is how you run the state,” he explained. “Sharia law is a long way from the modern nation-state as we know it.”

Some Western public figures have criticized Sharia law, citing the use of physical punishments.

Fear of legally enforceable sharia law taking root in the United States is widespread among conservative politicians and commentators, despite the fact that it plays no role in the U.S. legal system. Eleven states have taken proactive measures, enacting legislation to prevent sharia from being used in U.S. courts. Individual Muslims and Muslim communities use Sharia.

Sharia law has been the subject of legal challenges in the United States in recent decades, as some fear it will supersede U.S. law. Most legal and religious freedom experts believe that concerns about the use of Sharia law in the United States are based on a misunderstanding of legal realities. Sharia law, they say, is for religious groups to use to govern their internal operations but does not supersede US laws.

In some countries, Islamic rules governing women’s clothing have sparked heated debate, particularly interpretations requiring women to wear full burqa coverings. French law prohibits Islamic face coverings in public places, and other European countries have followed suit.

Interpretations differ across the Muslim world and, in many cases, within countries. Unlike the Islamic State or Saudi leaders, the Taliban considers itself to be a group of traditional Sunni Muslims who adhere to the Hanafi school of law, one of four traditional Sunni schools of Islamic jurisprudence.