The forces of the Quraish and the Arab tribes arrived beating drums, and raising shouts boasting, of their strength and invincibility. When they reached Madina, and found that a ditch intervened between them and Madina. They were confused as the Arabs were not used to ditch warfare. They set up their camps at some distance from the Ditch. Thus began the siege of Madina. The enemy made several attempts to cross the ditch, but the Muslim archers kept them at bay. The enemy approached the Jews of Banu Quraiza in Madina to help them in crossing the ditch. The Banu Quraiza were heavily bribed. They threw some dead animals in that part of the ditch where the Muslim defense was not very strong. Due to the treachery of the Banu Quraiza, some warriors of the Quraish led by Amr b Abdwoud managed to cross the ditch. Brandishing his sword, Amr challenged the Muslims to a duel in single combat; Amr was a formidable man who enjoyed the reputation of being equal to a thousand men in physical strength. Ali rose to accept the challenge. The Holy Prophet bade him sit down. Amr repeated his challenge for the second time, and Ali rose up once again to accept the challenge. The Holy Prophet once again asked Ali to sit down. Amr gave the challenge for the third time and Ali stood up again to accept the challenge. This time the Holy Prophet let Ali accept the challenge. When the duel began Ali appeared to be no match for Amr. Amr confident of his physical strength said to Ali that he did not want to kill him. Ali retorted that he intended to kill him. Amr succeeded in inflicting some wounds on Ali, but each time Ali aimed a blow, Amr successfully avoided the blows of Ali. When it appeared that the end of Ali was imminent, something miraculous happened. Amr imagined that some one was going to stab him in the rear. He turned his head. It was for a moment, but Ali took full advantage of the opportunity, and with a blow of his sword cut off the feet of Amr. Amr fell down, and Ali stabbed him to death. Thereupon Usl the son of Amr fell upon Ali. Ali was now as ferocious as a lion. He killed Usl with one stroke of his sword. Thereafter Naufal attacked Ali. Ali charged with full force, and while retreating Naufal fell in to the ditch, Ali jumped after him in the ditch and killed him there. Ikrama b Abu Jahl who had crossed the ditch along with Amr did not dare face Ali. He along with all other men who had crossed the ditch withdrew, and after again crossing the ditch found refuge in their camp. Ali was the hero of the day. It came to be felt that if Ali could overthrow Amr who was believed to be equivalent to a thousand men, Ali would be a man equivalent to ten thousand men. When the sister of Amr came to know that her brother had been killed she inquired from the people as to who had killed him, and when she came to know that Ali had killed him, she said that verily Ali was the bravest man among the Quraish.