He stepped forward and called out arrogantly, “Who is prepared to enter into a duel with me?” Hazrat ‘Ali (radhiyallahu ‘anhu) immediately asked Rasulullah (sallallahu ‘alaihi wasallam) for permission to go forward and enter into a duel with him saying, “O Nabi of Allah (sallallahu ‘alaihi wasallam)! I am prepared to enter into a duel with him!” However, Rasulullah (sallallahu ‘alaihi wasallam) replied, “Remain behind, for this man is ‘Amr (bin ‘Abd-e-Wudd who is very skilled in combat).”
‘Amr then called out for a duel again, and began to taunt the Muslims saying, “Where is the Jannah which you claim your martyrs will enter? Will none of you step forward to fight me?” Hazrat ‘Ali (radhiyallahu ‘anhu) again stood and sought permission from Rasulullah (sallallahu ‘alaihi wasallam), but once again, Rasulullah (sallallahu ‘alaihi wasallam) told him not to go forward and gave him the same reply as the first time.
The third time ‘Amr issued his challenge, Hazrat ‘Ali (radhiyallahu ‘anhu) again sought permission from Rasulullah (sallallahu ‘alaihi wasallam). This time, when Rasulullah (sallallahu ‘alaihi wasallam) said to him, “Remain behind, for this man is ‘Amr,” Hazrat ‘Ali (radhiyallahu ‘anhu) responded, “I do not mind fighting him, even though he is ‘Amr (bin ‘Abd-e-Wudd)!”
It was only then that Rasulullah (sallallahu ‘alaihi wasallam) permitted Hazrat ‘Ali (radhiyallahu ‘anhu) to go forward and accept the challenge of ‘Amr. Rasulullah (sallallahu ‘alaihi wasallam) gave him his sword, tied a turban on his head and made du‘aa for him saying, “O Allah! Assist him against ‘Amr!”
Hazrat ‘Ali (radhiyallahu ‘anhu) addressed ‘Amr and said, “O ‘Amr! You had pledged that if any man of the Quraish has to place two choices before you, you will certainly accept one.” ‘Amr replied, “Yes, that is true.” Hazrat ‘Ali (radhiyallahu ‘anhu) then said, “I thus invite you to Allah, His Rasul (sallallahu ‘alaihi wasallam) and to Islam.” ‘Amr replied, “I have no need for that.” Hazrat ‘Ali (radhiyallahu ‘anhu) replied, “I then challenge you to fight.” ‘Amr responded, “O my nephew! By Allah! I would not like to kill you!” Hazrat ‘Ali (radhiyallahu ‘anhu) replied, “However, I swear by Allah that I would love to kill you!”
This threw ‘Amr into a furious rage. He dismounted from his horse, cut its legs and then struck it on the face with his sword. He then advanced towards Hazrat ‘Ali (radhiyallahu ‘anhu) and swung his sword towards him. Hazrat ‘Ali (radhiyallahu ‘anhu) blocked his swing with his shield, but such was the power of the blow that the sword became embedded in the shield, causing it to split. The sword also reached the head of Hazrat ‘Ali (radhiyallahu ‘anhu) and caused it to be wounded.
Hazrat ‘Ali (radhiyallahu ‘anhu) then swung his sword, striking ‘Amr on the shoulder. Such was the might of Hazrat ‘Ali (radhiyallahu ‘anhu) that with this one blow, ‘Amr collapsed to the ground. Rasulullah (sallallahu ‘alaihi wasallam) was overjoyed at the victory of Hazrat ‘Ali (radhiyallahu ‘anhu) and called out the takbeer.
Hazrat ‘Ali (radhiyallahu ‘anhu) then returned to Rasulullah (sallallahu ‘alaihi wasallam), whose face was radiant with happiness. As he drew close, Hazrat ‘Umar (radhiyallahu ‘anhu) asked him, “Why did you not take his armor as booty, for among the Arabs, there is no armor better than his armor?” Hazrat ‘Ali (radhiyallahu ‘anhu) replied, “When I struck him, he exposed his satr (private part) towards me. I thus felt shame (to go near his body and remove his armor in that condition).”
It was on this occasion that Hazrat ‘Ali (radhiyallahu ‘anhu) recited the following couplets:
نَصَرَ الْحِجَارَةَ مِنْ سَفَاهَةِ رَأْيِهْ وَنَصَرْتُ رَبَّ مُحَمَّدٍ بِصَوَابِيْ
He (i.e. ‘Amr bin ‘Abd-e-Wudd) assisted idols due to his foolishness Whereas I assisted the (deen of the) Rabb of Muhammed (sallallahu ‘alaihi wasallam) due to being rightly-guided
فَصَدَدْتُّ حِيْنَ تَرَكْتُهُ مُتَجَدِّلًا كَالْجِذْعِ بَيْنَ دَكَادِكَ وَرَوَابِيْ
When I left him, I left him lying flat, like the trunk of a date palm lying among the sand dunes,
وَعَفَفْتُ عَنْ أَثْوَابِهِ وَلَوْ أَنَّنَيْ كُنْتَ الْمُقَطَّرَ بَزَّنِيْ أَثْوَابِيْ
And I refrained from (taking) any of his clothing. Had I been in his place, dripping with blood, then he would have still stripped me of my clothing
لَا تَحْسَبَنَّ اللهَ خَاذِلَ دِيْنِهْ وَنَبِيِّهِ يَا مَعْشَرَ الْأَحْزَابِ
O groups of Muslims! Do not ever think that Allah Ta‘ala will abandon His deen and His Nabi (sallallahu ‘alaihi wasallam) (and all those who follow Rasulullah (sallallahu ‘alaihi wasallam))
(Al-Bidaayah wan Nihaayah 6/40-45, Rowdh-ul-Unf 6/209-212 and Sharhuz Zurqaani 3/42)