It was the battle of Nahrawan against the Kharjites (Kharjite means one who rebels against religion) and Imam Ali ibn Abi Talib (as) himself was fighting like any other ordinary soldier. During this battle a man came to face him and in the encounter lost his sword. He realized his hopeless plight of standing before Imam Ali ibn Abi Talib (as) without any weapon in hand. Imam Ali ibn Abi Talib's (as) hand was raised for a blow when he saw the antagonist trembling with fear. Imam Ali ibn Abi Talib (as) lowered his hand slowly and said:
Run away friend you are not in a position to defend yourself.
This attitude made the man bold and he said: Ali ibn Abi Talib! Why do not you kill me? It would have made one enemy less for you.
Imam Ali ibn Abi Talib (as) replied: I cannot strike a man, who cannot defend himself. You were begging for your life and it was spared.
The opponent got bolder and said: I am told that you have never refused a beggar. Now I beg you of your sword, will you grant it to me?
Imam Ali ibn Abi Talib (as) handed him over the sword.
Taking possession of the sword he said: Now Ali ibn Abi Talib! Who is going to defend you against me and save you from my killing blow?
Of course Allah (SWT), He will defend me if He so wills. He has appointed my death to be my guarding angel none can harm before it is due and none can save me when it arrives.
Nobility of thought and action affected the foe and he kissed the bridle of Imam Ali ibn Abi Talib's (as) horse and said:
O Master, you are a great man indeed. You cannot only forsake the life of your enemy in a battle field but also you can grant him your sword. May I have the honour to act as your body guard and to fight for you?
Imam Ali ibn Abi Talib (as) replied: Friend! Fight for truth and Justice and do not fight for persons.
source : sibtayn
