Islamic Jurisprudence. This is an extremely large and very complex topic of Islamic studies.
The meaning of the word fiqh is understanding, comprehension, knowledge, and jurisprudence in Islam. A jurist is called a Faqih who is an expert in matters of Islamic legal matters.
A Faqih is to pass verdicts within the rules of the Islamic Law namely Shariah.
The most famous scholars of Fiqh in the history Muslims are the founders of the four schools of thought in (Sunni) Islam: Imam Malik, Imam Ash-Shafi’i, Imam Abu Hanifah, and Imam Ahmad.
Anything or action in Islam falls within the following five categories of Fiqh:
1. Fardh (Wajib): This category is a must for the Muslim to do such as the five daily prayers. Doing the Fardh counts as a good deed, and not doing it is considered a bad deed or a sin.
It is also called Wajib except for Imam Abu Hanifah who makes Wajib a separate category between the Fardh and the Mubah.
2. Mustahab/Mandub: This category is recommended for the Muslim to do such as extra prayers after Zuhr and Maghrib. Doing the Mandub counts as a good deed and not doing it does not count as a bad deed or a sin.
3. Mubah (Allowed): This category is left undecided and left for the person, such as eating apples or oranges. Doing or not doing the Mubah does not count as a good or bad deed.
Intention of the person can change Mubah to Fard, Mandub, Makruh, or Haram.
Other things could also change the status of the Mubah. For example, any Mubah becomes Haram if it is proven harmful, and any necessary thing to fulfill a Fardh is a Fardh too.
4. Makruh (Hated): This category is a detested and hated such as growing very long fingernails or sleeping on the stomach. Not doing the Makruh counts as a good deed and doing it does not count as a bad deed.
5. Haram (Prohibited): This category is prohibited for the Muslim to do such as stealing and lying. Doing the haram counts as a bad deed and not doing it counts as a good deed.