In the battle of Uhud...
In the battle of Uhud, a champion from the Makkan army rode out of his ranks and challenged the Muslims. Ali went out to meet him. Moments later, Ali had vanquished his opponent, and had planted his knee on his chest to deliver the coup de grace. In that moment, as a last act of defiance, the fallen champion spat on Ali.
It would have been a perfectly normal and human reaction on the part of Ali to have plunged his sword into the heart of the offender, who, now prostrate, had violated a rule of pagan chivalry – an unpardonable offense in Arabia. But Ali did just the opposite. He rose from the chest of his enemy, put his sword into the scabbard, and walked back to his own lines.
Both armies were watching this drama, and both were surprised but no one was more surprised than the enemy who had just been overcome, and could not believe that he was safe. What was the meaning of this strange act, he wondered; wasn't Ali going to kill him for his insolence? The Makkan hero rose from the ground, overtook Ali, and asked him why he did not kill him. Ali said: “Your foul act made me angry. Now if I were to kill you, I would find satisfaction against a personal injury.
But I am not seeking satisfaction against any personal injury. I do not want to kill anyone for any personal reason.” When the pagan warrior heard Ali's answer, his astonishment was even greater than before. But he understood that Ali was fighting for an ideal. Ali's answer accomplished what his sword had not; it destroyed the unbelief of his adversary, and he (the adversary) accepted Islam. This one act epitomized Ali's philosophy of life.
He demonstrated that his hatred, just like his love, was impersonal. He did not hate or love for himself; he hated or loved only for the sake of God. If he fought, it was only to win the pleasure of God; and if he made peace, it was also to win the pleasure of God. His whole raison d'être was to win the pleasure of God. If Ali disdained to kill for reasons of his principle, he also disdained to kill for reasons of his humanity.
It was to his humanity that a man as dangerous and treacherous as Amr bin Aas owed his life in the battle of Siffin. Abbas Mahmud Al-Akkad of Egypt writes in his book, 'Abqariyyet Imam Ali (Cairo, 1970): Ali's gallantry and chivalry did not allow him to take advantage of a situation in which he found his enemy cornered and helpless.