Truly speaking if we wish to find out the causes of the rising of the Imam we shall have to make a search for its preliminaries during a period of at least thirty years preceding that time, because about thirty years after the migration of the Holy Prophet, there had taken place such developments as had made necessary a movement like this in the Islamic society.
Uthman bin Affan Umavi ruled over the Muslims for about twelve years as the Caliph of Islam. It is clearly recorded in the history of Islam that the shape of the Islamic Government underwent a change during the six years covering the second half of the Caliphate of Uthman. In fact the Islamic rule should strictly enforce law otherwise the people should be free in all matters and no limits should be laid down for them except those prescribed by law. This Islamic method underwent a change and it assumed another posture that made the Muslim free in all matters, except that it was necessary for them to have regard for the interests of the ruler.
Taking advantage of this state of afairs the people began to amass wealth and property from the Baytul Mal (public treasury) of the Muslims. It was the same Baytul Mal that was guarded so carefully by Imam Ali during the period of his caliphate. The same policy was adopted by the caliphs preceding Uthman and even Uthman exercised necessary care in spending from it during the earlier part of his caliphate. However, later this wealth, instead of being spent on the general welfare of the Muslims, fell into the hands of a few persons. These were the malpractices, started thirty years earlier, which Imam Husayn decided to restrain in 60 A.H. by means of a sweeping and bloody revolution, which resulted in his own martyrdom and his everlasting honor.
Mas'udi writes in Murujuz Zahab that at the time of his death the Third Caliph left behind in cash 150,000 gold dinars and one million dirhams. However, according to the same Mas'udi, when Imam Ali was martyred Imam Hasan mounted the pulpit and announced: "My father has not left behind any gold or silver except 700 dirhams. This money, too, had been saved by him from his salary to procure a servant for his house".
Thereafter Mas'udi writes: "The value of the property owned by the Third Caliph in Wcidiul Qura and at other places reached 100,000 gold dinars. Besides it he also left behind a large number of horses and camels".
About Zubayr he writes: "Besides the well-known palace at Basra he built a large number of houses in Basra, Kufa and Alexandria and at the time of his death he owned 50,000 gold dinars, one thousand horses, one thousand slaves and slave-girls and numerous estates in different cities.
Talha bin Ubaydullah was a well-known companion of the Holy Prophet. His daily income from the property owned by him in Iraq alone reached 1000 gold dinars and according to another version it exceeded this amount. In Syria he owned even larger property.
Abd ur Rahman bin Awf Zuhari was one of the distinguished companions. He had 100 horses, 1000 camels and 10,000 sheep. At the time of his death he had four wives and as he had children also his wives inherited, according to the Islamic law of inheritance, 1/8 of the property left by him. This was decided between the four wives and every wife got 1/32 of the property. This 1/32 amounted to 84,000 gold dinars.
When Zayd bin Thftbit died he left behind such a large amount of gold and silver that it was broken with a hatchet and distributed among the heirs and the value of his other property was 100,000 gold dinars.
Yala bin Umayya, whose mother's name was Munayya, is also called Yala bin Munayya. The Battle of the Camel was started against Ali with his financial assistance and most of its expenses were borne by him. At the time of his death he left behind 500,000 gold dinars and the people also owed him large sums of money. Besides this the value of property etc. left by him was 300,000 dinars".
Thereafter Mas'udi himself writes: "During the Caliphate of Umar there was no such financial disorder and he did not permit these persons to grab all this wealth from the property of the Muslims. On the other hand everything was done in a straightforward manner and according to a clear-cut policy. In the light of the system of government and collection of wealth and its distribution among the Muslims none of the Muslims could acquire so much wealth.
After Caliph Uthman Imam Ali attained to the caliphate. The difficult task for Ali, on account of which battles were also fought, was to control these influential persons and not to permit any person any longer to take even one dinar from the Baytul Mal of the Muslims without proper accounting. He wanted to restrain the people from all sorts of covetousness, greed, and bad habits. For about four and a half years covering the period of his caliphate he had to struggle against these very persons who had been prevented by him from amassing wealth. He used to say: "It is no longer possible that I should be at the helm of affairs and this plundering should be renewed. On the contrary I shall recover whatever has been given or taken unlawfully and shall deposit it in the Baytul Mal". On this very account Ali was eventually martyred.
In these words as well as in his testament the Imam made his mission known to the people. He said: "I am going to enjoin the people to do good and to restrain them from evil". What did he mean by this? Possibly most of the people who heard these words of the Imam imagined that he wanted to go to Kufa and tell the grocers and bakers of that city: "Do not weigh less. Do not sell bad curd and cheese and improperly baked bread to the people". Or that he might tell the merchants of Kufa not to charge interest. This would be restraining from evil! Or that he might tell the residents of Kufa: "Do not be careless about obligatory prayers. If you can afford you must go to Makkah and perform Haj". This would be enjoining to do good. But the Imam's object was much higher than this. Of course this kind of enjoining to do good and restraining from evil is something good and essential, but this task could be performed by the ulema of Kufa and did not necessitate the Holy Imam's going there. In fact Imam Husayn wanted to do something which none else could do. In the conditions then prevailing it was only he, who could perform a memorable deed whose freshness cannot fade with the passage of time, and which cannot be effaced from the pages of the history of Islam.
source : http://abna.ir
