successors to Muhammad for the Twelvers. According to the theology of Twelvers, the successor of Muhammad is an infallible human individual who not only rules over the Muslim community with justice but also is able to keep and interpret the divine law (sharīʿa) and its esoteric meaning. The words and deeds of Muhammad and the Twelve Imams are a guide and model for the Muslim community to follow; as a result, they must be free from error and sin, and Imams must be chosen by divine decree (nass) through Muhammad. In Twelver Shīʿīsm, each Imam was the son of the previous Imam, with the exception of Ḥusayn ibn ʿAlī, who was the brother of Ḥasan ibn ʿAlī. The twelfth and final Imam is Hujjat Allah al-Mahdi, who is believed by Twelvers to be currently alive and hidden in Occultation. Jurisprudence The Twelver jurisprudence is called Jaʽfari jurisprudence. In this school of Islamic jurisprudence, the sunnah is considered to be comprehensive of the oral traditions of Muhammad and their implementation and interpretation by the Twelve Imams. There are three schools of Jaʿfari jurisprudence: Usuli, Akhbari, and Shaykhi; the Usuli school is by far the largest of the three. Twelver groups that don't follow the Jaʿfari jurisprudence include Alevis, Bektashi, and Qizilbash. The five pillars of Islam to the Jaʿfari jurisprudence are known as Usul ad-Din: Tawḥīd: unity and oneness of God; Nubuwwah: prophethood of Muhammad; Muʿad: resurrection and final judgment; ʿAdl: justice of God; Imamah: the rightful place of the Shīʿīte Imams. In Jaʿfari jurisprudence, there are eight secondary pillars, known as Furu ad-Din, which are as follows: Salat (prayer); Sawm (fasting); Hajj (pilgrimage) to Mecca; Zakāt (alms giving to the poor); Jihād (struggle) for the righteous cause; Directing others towards good; Directing others away from evil; Khums (20% tax on savings yearly, after deduction of commercial expenses). According to Twelvers, defining and interpretation of Islamic jurisprudence (fiqh) is the responsibility of Muhammad and the Twelve Imams. Since the 12th Imam is currently in Occultation, it is the duty of Shīʿīte clerics to refer to the Islamic literature, such as the Quran and ḥadīth, and identify legal decisions within the confines of Islamic law to provide means to deal with current issues from an Islamic perspective. In other words, clergymen in Twelver Shīʿīsm are believed to be the guardians of fiqh, which is believed to have been defined by Muhammad and