Twelver ((アラビア語:اثنا عشرية), Athnā‘ashariyyah or Ithnā‘ashariyyah; (ペルシア語:شیعه دوازدهامامی), ) Shia Islam or Imamiyyah ((アラビア語:إمامية)) is the largest branch of Shia Islam. The term ''Twelver'' refers to its adherents' belief in twelve divinely ordained leaders, known as the Twelve Imams, and their belief that the last Imam, Muhammad al-Mahdi, lives in occultation and will reappear as the promised Mahdi.
Twelvers believe that the Twelve Imams are the spiritual and political successors to the Islamic prophet Muhammad. According to the theology of Twelvers, the Twelve Imams are exemplary human individuals who not only rule over the community in justice, but also are able to keep and interpret ''sharia'' and the esoteric meaning of the Quran. The words and deeds (Sunnah) of Muhammad and the Imams are a guide and model for the community to follow; as a result, Muhammad and the Imams must be free from error and sin, known as Ismah or infallibility, and must be chosen by divine decree, or ''nass'', through Muhammad.
Twelvers make majorities in Iran, Azerbaijan, Iraq, and Bahrain; a plurality in Lebanon; and significant minorities in Kuwait, India,〔(【引用サイトリンク】title=Obama's Overtures )〕〔(【引用サイトリンク】title=Imperialism and Divide & Rule Policy )〕〔(【引用サイトリンク】title=Ahmadinejad on way, NSA says India to be impacted if Iran 'wronged by others' )〕 Pakistan, Afghanistan, Kuwait, Qatar, UAE and Saudi Arabia.〔(International Crisis Group. The Shiite Question in Saudi Arabia, Middle East Report No. 45, 19 September 2005 ).〕 Smaller minorities also exist in Oman, Yemen, Egypt, and Uzbekistan.
Twelvers share many tenets of Shia with related sects, such as the belief in Imams, but the Ismaili Shias believe in a different number of Imāms and, for the most part, a different path of succession regarding the Imamate. They also differ in the role and overall definition of an Imam. Twelvers are also distinguished from Ismailis by their belief in Muhammad's status as the "Seal of the Prophets" (Khatam an-Nabiyyin), in rejecting the possibility of abrogation of Sharia laws, and in considering both esoteric and exoteric aspects of the Quran.
Alevis in Turkey and Albania and Alawis in Syria share belief in the Twelve Imams with Twelvers, but their theological doctrines are remarkably different.
== Terminology ==
The term 'Twelver' is based on the belief that twelve male descendants from the family of Muhammad, starting with Ali ibn Abi-Talib and ending with Muhammad al-Mahdi, are Imams who have religious and political authority.
The Twelvers are also known by other names:
* The ''Shi'ah'' (or Shi'a) is commonly used as a synonym for "Twelvers" since this branch comprises the majority group in Shia Islam. ''Shia'' refers to a group of Muslims who believe that the succession to Muhammad must remain in his family for specific members who are designated by a divine appointment. Tabataba'ei states that the word referred to the partisans of Ali at the time of Muhammad himself.
* ''Ja'fari'' refers exclusively to the Twelver Juridical school which is followed by the majority of Shias. It also refers to the minority Akhbaris who advocate a distinct juridical approach within Jafari Jurisprudence. The term is derived from the name of Ja'far al-Sadiq who is considered by the Twelvers to be their Sixth Imām. Ja'far al-Sadiq is also respected and referenced by the founders of the Sunni Hanafi and Maliki schools of jurisprudence.
* ''Imami'' or ''Imamiyyah'' or ''Imamite'' is a reference to the Twelver belief in the infallibility of the Imāms. Although the Ismā'īlīs also share the generic concept of Imams, this term is exclusively used for the Twelvers who believe that the leadership of the community after Muhammad belongs to Ali and eleven subsequent successors that together comprise the Fourteen Infallibles.
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