Reasons of the failure of the Allies
In addition to the digging of the ditch, several factors contributed to the failure of the troops of the Allies:
(1) Disagreement between Ban£-Quray¨ah and the Allies
Nu`aym ibn Mas`£d, a member of Gha§af¡n tribe, had recently accepted Islam. Having acquired permission of the Holy Prophet to use deceptive tactics against the enemy, he met with Ban£-Quray¨ah and, pretending to be their friends, started reproaching them, saying, “Your position is different from Quraysh’s. If they lose the war, they will return home; but you have nowhere to go to if you lose. Muslims will then destroy you altogether.” He then suggested that they should take as hostages several chiefs of the Allies and keep them to the end of the war. He then revealed this military secret made by Ban£-Quray¨ah to the chiefs of Quraysh and Gha§af¡n, saying, “Ban£-Quray¨ah have decided to surrender to Mu¦ammad and give him these chiefs as a sign of goodwill.” He then warned them not to accept such a proposal. This plan worked well; differences developed between these two groups and the Allies were destroyed from within.
(2) The killing of `Amr ibn `Abd-Wudd
Quraysh had to bring the war to an end because they were pressure for three reasons:
First: Because the war took a longer period than expected, there was shortage in supplies.
Second: The weather became so cold that they could not bear staying inside tents.
Third: Dh£’l-Qa`dah, one of the sacred months in which fighting was forbidden, was approaching. If the war could not end in Shaww¡l, it would certainly be postponed for three months. Therefore, the Allies were determined to bring the war to an end at all costs. For this purpose, five of the bravest warriors jumped with their horses to the other side of the ditchand demanded equal opponents to fight. One of them was the famous Arab warrior, `Amr ibn `Abd-Wudd, who was famed as the hero of yalyal and the hero of Quraysh. Having crossed the ditch, `Amr shouted, “Is there any fighter to face me?”. None of the Muslim troops answered him. He repeated this call seven time and each time Imam `Al¢ would rise and ask the Holy Prophet to permit him to confront this warrior. Finally, permission was given to Imam `Al¢. As he proceeded to confront `Amr, the Holy Prophet said,
“The entire Islam will face the entire unbelief.”
In a great duel, Imam `Al¢ could kill `Amr. Seeing this, the other four warriors who had passed the ditch flew. One of them had fallen in the ditch with his horse before he was killed by Muslims.
Seeing this great bravery of Imam `Al¢, the Holy Prophet said,
“Your deed today is superior to all deeds of Muslims put together. As `Amr is killed, all houses of the enemies are miserable and all houses of Muslims feel dignity.”
On the word of al-°¡kim al-Nays¡b£r¢, a great Sunni traditionist, the Holy Prophet had declared:
“`Al¢’s fighting with `Amr at the ditch is more favorable than the good deeds of all Muslims up to the Resurrection Day.”
With the killing of `Amr, the Allies lost their morale; signs of defeat appeared in their camp so evidently that each tribe decided to retreat.
(3) Divine Assistance
The last blow to the enemy was done by God Who caused a terrible storm to dominant over them at night. The storm destroyed their tents completely. As a consequence, Ab£-Sufy¡n ordered them to return to Mecca. Referring to this victory, God the Almighty states in the Holy Qur'¡n:
O you who believe; call to mind the favor of Allah to you when there came down upon you hosts; so, We sent against them a strong wind and hosts that you saw not, and Allah is Seeing what you do. (33:9)
And Allah tuned back the unbelievers in their rage; they did not obtain any advantage, and Allah sufficed the believers in fighting; and Allah is Strong, Mighty. (33:25)
Despite the enemy’s great expenditure on his war, the results of were bitter and disastrous because they could neither damage Medina nor free the Damascus trade route. In this way, Ab£-Sufy¡n’s military credit was greatly damaged and the status of Quraysh was badly hurt. After this war, Muslims had more courage to attack their enemy. The Holy Prophet said, “From now on, we will attack and they will have no ability to attack us.” The martyrs in this war are reported to be six and the enemy casualties were three.
 The Holy Prophet is reported to have said, “War depends upon tactics.”
 Ibn Sa`d, op cit, 2:64; Ibn Hush¡m, op cit, 3:240; ±abar¢, op cit, 3:50-51; °alab¢, op cit, 2:650; Samh£d¢, op cit, 1:304; al-Majlis¢, op cit, 20:207.
 Mu¦ammad °am¢dull¡h, Ras£l Akram dar Mayd¡n Jang, pp. 128.
 Ibn Sa`d, op cit, 2:68; al-W¡qid¢, op cit, 2:470; ±abar¢, op cit, 3:48; Shaykh al-Muf¢d, al-Irsh¡d; al-Majlis¢, op cit, 20:203.
 At a place called Yalyal, `Amr, alone, fought a group of enemies. See Bi¦¡r al-Anw¡r 20:203.
Because he had been wounded at the Battle of Badr, he did not participate in the Battle of U¦ud. See Ibn Hush¡m, al-S¢rah al-Nabawiyyah 3:235; ±abar¢, T¡r¢kh al-Umam wa’l-Mul£k 3:48; Ibn al-Ath¢r, al-K¡mil f¢’l-T¡r¢kh 2:181.
 al-W¡qid¢, op cit, 2:470; Ibn Ab¢’l-°ad¢d, Shar¦ Nahj al-Bal¡ghah 13:291 and 19:63; al-Majlis¢, Bi¦¡r al-Anw¡r 20:203.
 Ibn Ab¢’l-°ad¢d, op cit, 19:61; al-Majlis¢, op cit, 20:215.
 al-Bul¡dhar¢, op cit, 1:345; Mu¦ammad Ibn Sa`d, op cit, 2:68; Ibn Hush¡m, op cit, 3:236; ±abar¢, op cit, 3:48; Samh£d¢, op cit, 1:303.
 Al-Kar¡jak¢, Kanz al-Faw¡'id 1:298; al-Majlis¢, Bi¦¡r al-Anw¡r 20:205-216.
 Al-°¡kim al-Nays¡b£r¢, al-Mustadrak `Al¡’l-¯a¦¢¦ayn 3:32.
 Al-Kar¡jak¢, op cit, pp. 299.
 al-Bul¡dhar¢, op cit, 1:345; Ibn Sa`d, op cit, 2:71; ±abar¢, op cit, 3:51-52; Ibn Shahr¡sh£b, Man¡qib 1:198; ±abars¢, I`l¡m al-War¡, pp. 92; Samh£d¢, op cit, 1:305; al-Majlis¢, op cit, 20:208-209.
 Shaykh al-Muf¢d, al-Irsh¡d, pp. 106; ¯a¦¢¦ al-Bukh¡r¢ 5:215; ±abars¢, Majma` al-Bay¡n 8:345; al-Majlis¢, op cit, 20:209.
 Ibn W¡¤i¦, T¡r¢kh al-Ya`q£b¢ 2:42; al-W¡qid¢, al-Magh¡z¢ 2:492; Ibn Hush¡m al-S¢rah al-Nabawiyyah 3:264; ±abar¢, op cit, 3:58; Ibn Shahr¡sh£b, Man¡qib 1:198.
The number of the martyrs of this war is reported to have been higher than this. See Mu¦ammad Ibr¡h¢m ªyat¢, the History of the Prophet of Islam, pp. 372.
 al-W¡qid¢, op cit, 2:496; Ibn Hush¡m, op cit, 3:265; ±abar¢, op cit, 3:59; Ibn Shahr¡sh£b, op cit, 1:198. Ya`q£b¢ has recorded the number of martyrs as eight.(T¡r¢kh al-Ya`q£b¢ 2:42).