From the advent of Islam and following the lead of Prophet Muhammad (pbuh&hf) and the immaculate Imams (as) from his household, the Shias have always insisted that caliphate neither can be nor has been delegated to people themselves to appoint whom they wish to lead the Muslim community and, based on Islamic teachings, not anyone who assumes power is fit for this position. If such a person assumes power, his rule would be illegal and this is what sparked Imam Hussian's revolutionary uprising.
Were it not for innumerable proofs and evidence which leave no doubt for anyone, it would have been hard to believe that just 50 years after the demise of the deeply and greatly revered Prophet Muhammad (pbuh&hf), the Islamic society had fallen so deep in decadence that an army of 30 thousand people participated in the killing of his beloved grandchild.
Despite knowing the high position of Imam Hussain (as) and that how much the Prophet (pbuh&hf) loved him, those who came to defend him were fewer than 200 individuals. What makes this incident even more tragic is that he was savagely martyred along with his children (including a six-month-old baby), relatives and companions while they had been deprived of water for days near the big river of the Euphrates. The enemy’s inhumane treatment of the household of the Prophet (pbuh&hf) did not end there but they held the surviving grieving women, little girls and small children captive and moved them forcefully all the way to Kufah and from there to Damascus while the heads of the martyrs were on spearheads in front them.
What makes the event even more shocking is that many of those who participated in the killing of Imam Hussain (as) and his companions, actually did that with the intention of getting closeness to God. This incident is clear proof that if power is left in the wrong hands, how deeply and quickly a society could fall into decadence and corruption. The leadership of the society being in the right hands is so important that in the Quran, rejecting the leadership of tyrants and illegitimate rulers has been mentioned along with belief in Allah,
We have dispatched a messenger to every nation [who said]: "Serve God [Alone] and turn aside from the Arrogant ones." Some of them God has guided, while others there are for whom error has been confirmed. Travel around the earth and see how the outcome was for those who deny [everything]. (16:36)
From the advent of Islam and following the lead of the Prophet (pbuh&hf) and the immaculate Imams (as) from his household, the Shias have always insisted that caliphate neither can be nor has been delegated to people themselves to appoint whom they wish to lead the Muslim community and, based on Islamic teachings, not anyone who assumes power is fit for this position. If such a person assumes power, his rule would be illegal and this is what made Imam Hussian (as) stage his revolutionary uprising.
The Shias believe that in his farewell pilgrimage to Mecca near the pond of Ghadir Khumm, the Prophet (pbuh&hf) officially and publically announced Ali ibn Abi Talib (as) as his successor, though he had hinted at that in many other places already. If as instructed Imam Ali (as) had assumed power right after the demise of the Prophet (pbuh&hf), the Islamic history would have followed a completely different course. Not only would the tragic and bitter incident of Karbala not have occurred but the corrupt, cruel and far removed from Islamic teachings Umayyad and Abbasid caliphs like Yazid would not have usurped caliphate. As a result, today we wouldn’t have been witnessing these many denominations, clashes, hostility, hatred, extremism, excommunication and hatred toward each other among Muslims.