Ali (r.a) made couple of attempts at negotiating with Muawiyah (r.a), so no Muslim blood would be spilt. Muawiyah responded with:Historian Yaqubi wrote that Ali had 80,000 men, including 70 Companions who participated in Badr, 70 Companions who took oath at Hudaibia, and 400 prominent Ansars and Muhajirs; while Muawiya had 120,000 Syrians.[2]
After such response, Ali was the first to march towards Muawiyah's camp, initiating the civil war, as some might argue.Even at this stage, Ali sent three men, viz. Bashir bin Amr bin Mahz Ansari, Saeed bin Qais Hamdani, and Shis bin Rabiee Tamini to Muawiya to induce him to settle for union, accord and coming together. According to Tabari, Muawiya replied that, "Go away from here, only the sword will decide between us."[1]
The Battle of Siffin was the 2nd Civil War of the Muslims, making the Battle of the Camel was the 1st Fitnah or Civil War and it involved Ali and his supporters against faction led by Talhah (r.a), Al-Zubayr (r.a) and Muhammad's wife, Aisha bint Abu Bakr (r.a).Seeing that war was inevitable, Ali gathered his forces, and, after at first planning to invade Syria from the North, he attacked directly, marching through the Mesopotamian desert.
So, who was really at fault?