What is the truth of the matter twelve imams according to the Ahl-i Sunnah-close followers of Prophet Muhammad (peace be upon him), and to the Shia?

Although the Shia is divided into some subdivisions like Galiya, Zaydiyya, and Imamiyya, today with the term Shia, usually Imamiyya is meant.

They accept Hazrath Ali (may God be pleased with him) and respectively his two sons and grandchildren as the legitimate imam (caliphate) with the decree of God and the will of Prophet Mohammad, after the Prophet (pbuh) has passed away; and thus see it a pillar of faith to believe in the twelve imams. Because this group accepted only the twelve imams, they are called Isna Ashariyya; and because they take it as one of the pillars of faith to believe in the Imams, they are called Imamiyya; and because they base both their belief and prayers and conducts on the views of Imam Jafar as-Sadık, it is called Jafariyya.

The Shia is of the opinion that the Imamet, i.e. the caliphate, is not one of the simple things that can be left to the choice of the Muslims, as the Ahl-i Sunnah accepts. They think the caliphate is among the pillars and essentials of religion and thus the Shia must believe in the existence of the imam, as they must in God, the prophets, and the Hereafter. According to this view, the caliphs are pure like the prophets. They do not commit either small or big sins. Whoever does not accept them is in blasphemy. Moreover, their commands are the commands of God; their bans the bans of God. Obedience to them is obedience to God; riot against them is riot against God.

Today, Iran acknowledges the Imamiyya as an official sect, and gives the responsibility of imamet, which contains religious authority to Ayetullahil-Uzma. For this reason, people must obey this imam. It is like opposing to God and the Prophet to oppose him. It is accepted as an important essential in the Iranian constitution to believe in the twelve Imams, as is openly stated, The official religion of Iran is Islam, and official sect is Isna Asharri Jafari. And this article cannot be altered forever.(1)

The issue of caliphate is not included in the system of religion for the Ahl-i Sunnah, as opposed to the Shia. The imam, i.e. the caliph comes to power through an election and with the votes of the Muslims. Anyone with certain religious and worldly qualities can undertake the management of the Muslims. In no way can he be sinless and innocent.

When we come to the way Ahl-i Sunnah sees the twelve Imams; the eleven Imams (twelve with Hazrath Ali)-the descendants of Prophet Muhammad (pbuh)- are each great people of knowledge and wisdom in terms of virtues, avoidance of evils and spiritual ranks.
Bediüzzaman recounts the twelve Imams, when he counts the addressees of the hadith: The learned of my community are like the prophets of the Children of Israel.(2) In his another statement; he introduces the twelve Imams as the great people of Ahl-i Sunnah, by describing the people of knowledge as the four Imams of sects and the twelve Imams.(3)

The twelve Imams are as follows: Hazrath Ali, Hazrath Hasan, Hazrath Hussein, Ali bin Hussein, Muhammad Bakır, Jafar-i Sadık, Musa Kazım, Ali Rıza, Muhammad Taki, Ali Naki, Hasan Askari, and Muhammad Mahdi (may God be pleased with them all)

Sources:
1. Çağımızda İtîkâdî İslâm mezhepleri, s. 118-139; Muvazzah îlm-i Kelam,s. 24-25.
2. Şualar, s. 527.
3. Emirdağ Lahikası, 1:201