At the Battle of the Ditch, the noble Imam 'Ali had knocked an enemy soldier to the ground and was raising his sword to kill him, when the unbeliever spat in the blessed face of the Valiant Lion, may Allah be pleased with him. Imam 'Ali at once stood still and refrained from killing his enemy. Hardly able to believe his own eyes, the unbeliever asked: "Why have you spared me, O gracious one?"
To this, the noble 'Ali replied:
"Your property and your life have become sacrosanct to me. I am not authorized to slay you. I can receive permission to kill only in holy combat, in fighting commanded by Allah. Just a few moments ago, I had overcome you in battle, knocked you to the ground and was on the point of slaying you. But when you spat in my face, my selfish anger was aroused against you. If I had killed you, I would have slain you not for Allah's sake but for my own selfish reason; they would then have called me not a champion warrior, but a murderer. When you spat in my face, my selfish passion threatened to overwhelm me, so instead of striking you with the sword for my own sake I struck my passion for the sake of Allah, Exalted is He. There you have the reason for your escape."The unbeliever was left in awe and amazement. This event made him realize that he was a direct witness to the worth and value of being Muslim. As he felt the light of Islam descending into his heart, he was quite unconscious of the tears streaming down from his eyes. He could he be aware of them? ... In the space of a few seconds he was being saved from dying as an unbeliever -- saved from being an unbeliever at all -- and was becoming a Muslim. Moreover, the cause of his conversion, the person standing before him, was none other than the Noble Imam 'Ali (Radhi Allahu Ta'ala Anhu). Indeed, friendship and affection, as well as enmity, should be in the manner determined by Allah. That is to say, the object to be ever kept in view is the good pleasure of the Exalted Lord.