al-Sulami, known as Abu'l-A'war (the one eyed), who once opposed Muhammad and is credited with depriving the Iraqis from drinking water prior to battle. On the other side, Kennedy suggests that Malik al-Ashtar was an inspiration on the battlefield to many of the Iraqis, at one point saving his men from fleeing in panic. Early on, he is said to have challenged Amr ibn Sufyan to single combat, but the latter refused. On the second day, Mu'awiya concentrated his assault on Ali's left wing but his forces were pushed back by the Iraqis. Mu'awiya was compelled to flee his pavilion and took shelter in an army tent. On this day, Ubayd Allah ibn Umar was killed fighting for Mu'awiya. He had earlier fled to Syria when he learned that Ali intended to punish him for murdering some Persians innocent in the assassination of Umar. On the other side, Ammar ibn Yasir, an octogenarian companion of Muhammad, was killed fighting for Ali. In the canonical Sunni sources Sahih al-Bukhari and Sahih Muslim, a prophetic hadith () predicts Ammar's death at the hands of () who invite to hellfire. On the third day, Mu'awiya turned down the proposal to settle the matters in a personal duel with Ali, brought forward separately by Ali and some of Mu'awiya's followers. Urwa ibn Dawud al-Dimashqi volunteered to fight instead of Mu'awiya and was promptly "cleft in two" by Ali. After another indecisive day, the battle continued throughout (). Unlike Ali, Mu'awiya did not allow the enemy to recover and bury their dead when he advanced. It was perhaps around this time that Mu'awiya repeated his earlier offer for peace in return for the rule of Syria, according to Ibn Muzahim. His account adds that Ali rejected the offer again, saying that he would not abandon against the enemies of God, even if he were to be killed in His way seventy times and revived each time. According to the same source, also around the same time did Mu'awiya send his brother Utba to negotiate a separate truce with al-Ash'ath ibn Qays, the influential Yemenite tribal leader, who was not closely associated with Ali or his cause. Call to arbitration By the next morning, the balance had moved in favor of Ali, as also suggested by al-Tabari and al-Baladhuri. Before noon, however, some of the Syrians raised pages of the Quran on their lances, shouting, "Let