The concept of Imamate or Leadership in Islam is a concept which is present in all schools of Islamic theology and jurisprudence.
This is because all schools recognise the need for a leader. However, the scope of the authority of Imamate and its specifications are subject to intense intellectual debates amongst the different schools. According to the Shi’a School of Theology, Imamate is one of the five Usul al-Din (Pillars of the Religion) and it is necessary for one to believe in it in order to be recognised as a Shi’a.
Unlike their counterparts in other schools of theology, the Shi’a believe exclusively in the doctrine known as nass; explicit designation that is divinely guided.
They hold that the Imam is an individual who possesses the same characteristics as Prophets (though are not Prophets as they do not receive revelation) and must also be divinely protected in the same way that Prophets are. According to Shi’a, the Imams appointed by Allah (s.w.t) to succeed the Prophet (s.a.w) are twelve individuals who successively succeeded one after the other. These individuals are the best from amongst the Ummah and were selected by Allah (s.w.t) due to their exceptional qualities.
Unlike Sunnis, Shi’a completely reject the belief in selection of the Imams by Shura (consultation) and argue that the office of Imamate is not something which is the right of the people to decide, in the way in which the masses can elect a political leader.