But the Shiah believe that the Quran contains both an explicit message accessible to all Muslims, and an implicit message meant solely for them. This is, of course, a common belief among sectarian movements. The early Christians, for example, eagerly sifted through the Hebrew Scriptures looking for anything that could be interpreted as an allusion to Jesus. In the same way, the Shiah scoured the Quran and found within its pages numerous references to justify their distinctive beliefs and practices. They also possess a secret, esoteric knowledge passed down through a mystical transfer of consciousness from God to Muhammad, from Muhammad to Ali (and his wife Fatima, Muhammad's daughter), from Ali to Hasan (Ali's eldest son) and Husayn, and down to the rest of the Holy imams.
The word "imam" has multiple connotations. In Sunni Islam, the imam is simply the person who stands at the head of the mosque and leads the congregation in prayer. For the Shiah, however, the imam is a divinely guided leader and the living spirit of the Prophet. As the executor of God's will, the Shiite imam is infallible and sinless. He is created not from dust, as other humans are, but from eternal light. He has access to extra-Quranic texts such as The Book of Fatima, which recounts God's revelations to Fatima after Muhammad's death. He knows the secret name of God and is ultimately the only person with the spiritual power necessary to reveal the inner truth of the Muslim faith.
The Sunnis consider the Shiite conception of the imam to be a heretical innovation, at odds with the principal belief of Islam that God is unrivaled, inimitable, utterly unique, and completely indivisible. To claim that the imam is sinless and divinely guided, that he is different from the rest of humanity is, for Sunnis, akin to giving a human being equal status with the Almighty.
The Shiah counter that the imam is in no way equal to God. Like Catholic saints, he is merely set apart from the rest of humanity. The imam may be prayed to for intercession, and he may have the power to heal the sick, but his authority is derived solely from his connection to the Prophet. And just as there are a fixed number of prophets, ending with Muhammad, so are there a fixed number of imams, ending with "the Hidden Imam," known as the Mahdi.
Nearly all Muslims acknowledge the existence of the Mahdi, a messianic figure who will return at the End of Days to usher in a time of peace and justice. Sunni and Shiah alike believe the Mahdi's coming will be an apocalyptic event portended by earthquakes, wars, famine, and false prophets. In Islam, the Mahdi's returnwill herald the return of Jesus; both prophets will rule the next world together.
However, as the Shiah shaped the doctrine of the Mahdi into the central tenet of their faith, Sunni scholars began to distance themselves from further speculation on the topic in an attempt to separate themselves from what fast became a politically disruptive ideology. That's because according to the Shiah, the Mahdi's principal task upon returning to earth will be to avenge the injustice inflicted by the Sunni authorities upon Husayn and hisfollowers at Karbala.
So, when Muqtada Sadr and his band of disaffected and impoverished Iraqi youths managed, during those first hectic months after the fall of the Sunni tyrant Saddam Hussein, to take control of the sacred cities of Kufa, Karbala, and Najaf, it seemed that the Army of the Mahdi had truly arrived to finally avenge Husayn. Sadr has stoked the traditional sentiments of Iraq's Shiite community by brazenly framing his rebellion in apocalyptic terms. He sets himself apart as the herald of the messiah and calls his followers the last true Muslims in Iraq. Taking refuge next to the body of the blessed Imam Ali, in what was once the most glorious shrine in Shiism (but which has now become a wrecked and ramshackle garrison), Sadr claims he is fighting a holy war against both foreign oppressors and treasonous hypocrites. Vowing to follow in the footsteps of Husayn, he has convinced his ragged band of followers to fling themselves recklessly at American troops, only to be mowed down by the hundreds.
Of course, now that most of Iraq has turned against him and the American and Iraqi forces seem intent on capturing or killing him once and for all, the End of Days may be nearer for Sadr and his Army of the Mahdi than they think.