The Imam chose the good persons to rule the cities. So, he appointed Malik al Ashtar ruler over Mousal, Sinjar, Naseebeen, Heet, and Anat. They are areas on the borders of Shaam.
Mu'awiyah disobeyed the Caliph. He became a dictator in Shaam.
The Imam tried to persuade Mu'awiyah to obey him. He sent him several letters, sent some delegates to talk with him. But all the Imam's efforts were in vain.
Thus the Imam formed an army and gave its leadership to Malik al-Ashtar.
The army advanced towards Shaam. It arrived in Kirkeesya, where it clashed with the Shamian Army headed by Abi al-Awar al-Salmy.
Malik al-Ashtar tried to persuade the leader of the army to end the mutiny and to obey Amirul Mu'mineen, but he refused.
At night, the Shamian Army took advantage of time and launched a surprise attack. That action was contrary to the religion and politeness because the two parties were in negotiations.
The Caliph's Army resisted the surprising attack. It killed and wounded many attackers and forced the others to withdraw to their original places.
Again Malik al-Ashtar showed his bravery. He sent a man to Abi al-Awar to invite him to duel with swords.
The man said:
Abi al-Awar, Malik al-Ashtar is inviting you to duel with him!
The leader of Mu'awiyah's Army became afraid and with cowardice said:
I don't want to duel with him!
Mu'awiyah headed a big army to join the Shamian Army.
The two armies met in the plain of Siffeen on the banks of the Euphrates.
Some units of Mu'awiyah's Army occupied the banks and besieged the river.
That action was also contrary to the laws of Islam and the laws of war.
The Imam sent Sasaah bin Suhan, one of the companions of the Prophet [s], to Mu'awiyah to talk with him.
Sasaah came into Mu'awiyah's tent and said:
Mu'awiyah, Ali says:
"Let's take some water. Then we'll decide what's between you and us, otherwise we will fight each other till the victor drinks."
Mu'awiyah kept silent and said:
I'll answer you later on.
The Imam's representative went out. Mu'awiyah asked the advice of some men. So al-Waleed said with spite:
Prevent them from drinking water to force them to surrender.
They agreed on this opinion.
Mu'awiyah gathered all the evil persons around him. They violated the laws of Islam and of human rights.
Malik al-Ashtar was watching the military movements on the river banks. He saw military supplies. So, he realized that Mu'awiyah would tighten the siege.
The Imam's soldiers became thirsty. Malik became thirsty, too. So, a soldier said to him:
There's only little water in my water-skin, please drink it.
Malik refused that and said:
I won't drink till all soldiers drink!
Malik went to the Imam and said:
Amirul Mu'mineen, our soldiers are very thirsty. We've nothing but fighting.
The Imam answered:
The Imam gave the soldiers a speech and urged them to fight bravely.
Then he said:
Death is that man is pleased with abasement. And life is that man who dies and becomes a martyr.
Malik led the first attack at the Battle of Siffeen. And he began fighting bravely. So, he advanced towards the banks of the Euphrates.
After violent clashes, Malik could recapture the river banks and force Mu'awiyah's Army to withdraw.
Mu'awiyah's Army became far from water. So, they thought of a trick to recapture its places on the River Euphrates.
On the following day, an arrow fell among the Imam's soldiers. There was a letter tied to the arrow. The soldiers read the letter carefully. They passed on the news quickly to each other. The news was:
From a loyal brother in the Shamian Army, Mu'awiyah is going to open the river to drown you. So, be careful!
The soldiers believed the news and withdrew. The Shamian Army took advantage of the situation and recaptured the river banks.
But the Imam's Army launched a general attack and dismissed the Shamian Army from the region.
Mu'awiyah was so worried that he asked Amru bin al-Aas:
Do you think Ali will prevent us from drinking water?
Amru bin al-Aas answered:
Ali doesn't do as you do!
The Shamian soldiers were worried, too. Immediately, the soldiers heard that Imam Ali [a] allowed them to come to the river to drink water.
Some people from Shaam realized the difference between Mu'awiyah and Ali. Mu'awiyah did every evil action for victory. But Ali did not think about that at all. He conformed to the human, good, ideal behaviour.
Thus, the soldiers of the Shamian Army left Mu'awiyah's front secretly at night. They joined Ali's front because it was always representing truth and humanity.