Hua'i Ibn Akhtab was the biggest habitual troublemaker among Banu Nadir who had settled in Khaibar along with the larger section of the Jews who were banished from Al-Madinah. Hua'i Ibn Akhtab, Salam Ibn Abul-Huqaiq, Salam Ibn Mishkam and Kinanah Ibn Ar-Rubaiyi' were the prominent chieftains of Banu Nadir. They along with Hud Ibn Qais and Abu Umarah, the chieftains of Banu Wa'il, went to Makkah and started raising funds for another battle and the Quraish made lavish contributions to it.
After collecting huge amounts of wealth and exciting the people to the extreme, they went the Ghatfan clans and played the same role there. Banu Kinanah also jumped on the bandwagon. Finally they made contacts with Banu Quraithah of Al-Madinah who were still bound to help the Muslims according to the pact signed by both the parties. Banu Sulaim, Fazarah, Ashja', Banu Sa'd and Banu Murrah, and the chieftains of the Quraish, Banu Nadir and Ghatfan that were not less than fifty in number, all went to the Ka'bah and vowed to fight against the Muslims as long as they lived.
They maintained great caution and tight security in view of their past experiences, so the Prophet [Sallallahu Alayhi Wa Sallam (SAWS) / peace be upon him] did not receive any news about this greatest conspiracy hatched against Islam until it was too late for the Muslims to do anything.
According to their plan, Abu Sufyan set out from Makkah at the head of four thousand soldiers collected from the allied tribes. At Marr-az-Zahran the troops of Banu Sulaim also joined the Makkan army; other of their allies kept on joining on the way. Hua'i Ibn Akhtab was the chief of Banu Nadir, and the chief of the Ghatfan tribes was Uyainah Ibn Hisn, while Abu Sufyan was the commander in chief of the allied forces.
Coming close to Al-Madinah, the total number of the allied forces came at least to ten thousand or twenty-four thousand according to some narratives. It consisted of four thousand five hundred camels and three hundred horses.
When the Prophet (SAWS) received news of their nefarious design to invade Al-Madinah, he called a meeting to decide on how to face an enemy with far superior numbers and weaponry. They all agreed to fight a defensive war. Salman Farisi (the Persian) [Radhiallahu Anhu (RA) / may Allah be pleased with him] is reported to have said, "When we feared a charge by the cavalry, we used to dig trenches to keep the invaders at bay." The Prophet (SAWS) agreed to his suggestion and decided to have a trench dug in the open ground lying to the north of Al-Madinah.
The city was exposed only on that side and was well-protected to the west, south and east by large plantations of date palms, volcanic rocky plains and granite hills presenting considerable obstacles to the progress of a mounted enemy. This was, in fact, the fort of the Muslim troops. In the middle, the Prophet (SAWS) pitched his camp. The trench was dug five yards wide and five yards deep. Groups of ten persons were each assigned the task of digging a part of the trench after equal division of the whole area. The Prophet (SAWS) was performing the same work along with his loving Companions.
A large rock was causing great difficulty in digging the trench for it could not be broken by the pick. When the Prophet (SAWS) was informed, he dropped down into the trench and gave such a blow with the pick that the rock was split and a glowing light came out of it. He (SAWS) said, "Allahu Akbar (Allah is the Most Great), the keys of Syria have been given to me."
With the second blow of the pick, the Prophet (SAWS) split another portion of rock and said, "Allah is the Most Great, the keys of Persia have been given to me." On the third attempt the remaining portion of the rock was broken to pieces. The Prophet (SAWS) then said, "Allah is the Most Great, I have been given the keys of Yemen." He then added, "Jibril (Gabriel) the trustworthy has given me glad tidings that all these countries will be under the possession of my Ummah (society)."
At a time when the Muslims were making a desperate effort to save their lives against an army of twenty-four thousand strong and when all of Arabia seemed to be thirsty for their blood, glad tidings of the conquest of Persia, Rome and Yemen were given to the Muslims. No one but Allah the Almighty Alone could do such a thing.
Meanwhile news came to the Prophet (SAWS) that even Ka'b Ibn Usaid, the chieftain of Banu Quraithah had joined hands with the invaders and Hua'i Ibn Akhtab had made a friendly entry into the citadel of Banu Quraithah to rouse them against the Muslims. The Prophet (SAWS) sent Sa'd Ibn Mu'ath and Sa'd Ibn Ubadah to Banu Quraithah to bring them back to their senses but in vain. In reply to the polite and sensible approach, they very harshly replied that they knew of no Muhammad nor did they have any commitment with him.
When the enemy troops drew near, they exclaimed in amazement at the sight of the trench for it was a new experience for the Arabians. They laid siege of Al-Madinah. It was the "most tremendous show of military power and strength on the part of the polytheists. The Muslims had managed to send their women and children to a nearby citadel. A sudden attack by the Jews, who happened to be within the bounds of Al-Madinah, was looming large over the Muslims of Al-Madinah. The hypocrites could prove even more injurious as they were always mixing with them.
Many times the disbelievers tried to cross the trench but failed. They inspected 'the trench and, at last, found out a spot where it was narrowest and their horses jumped over the moat and carried their riders into the territory of Al-Madinah. One of these was the well-known warrior, Amr Ibn Abd Wadd who was considered a match for two thousand horsemen.
Ali Ibn Abu Talib (RA) cut off his head with a sweeping slash of his scimitar. The rest who had stormed the trench with him darted back on their horses. Then the actual fight started and both sides got engaged in an exchange of arrows, which would continue from morning till evening. This siege lingered on for about a month, which was very difficult and troublesome. The enemy camp was getting reinforcements from outside supporters but the Muslim's were deprived of any such help.
Once a Companion complained to the Prophet (SAWS) of being exhausted by hunger, and showed him his stomach on which he had tied a slab of stone to keep himself straight and active. The Prophet (SAWS) then showed him his own belly on which he had tied two slabs of rock.
Since they were constantly under the fear of being sniped at by the enemy, the Muslims used to keep guard the whole night under the open sky besides being engaged in facing the enemy the whole day. Mus'ab Ibn Qushair, a hypocrite, tauntingly remarked: "Though the Prophet is giving Syria, Iran and Yemen to his Companions, I see in fact that they are now unable to even live in Al-Madinah. Some of them used to say, "They cannot even go out to answer the call of nature but see the dream of conquering the empires of Caesar and Chosroes.
The Muslims were in a state of a long-drawn-out siege. They were facing the scorching sun in the day, hunger, the lurking danger of an enemy charge any time, and the nefarious activities of Banu Quraithah and the hypocrites of Al-Madinah.
Mounting pressure of enemy power and strength on one hand, and the lack of men and material on their side, the Muslims were so determined and dauntless that whenever they were asked to accept peace at the cost of their honor, they rejected the offer totally. Even in such a period of distress and desperation, noble and fortunate souls were coming into the fold of Islam.
Suddenly one day Nu'aim Ibn Mas'ud, belonging to the Ghatfan tribe, came to the Prophet (SAWS) breaking away from the enemy camp and embraced Islam. He then said that he had a mission to sow the seed of discord between Banu Quraithah and the Makkan army. Thus, he first went off to Banu Quraithah and then to Abu Sufyan and talked in a way that both of them grew doubtful of each other.
As a result of this, Banu Quraithah held back from lending any concrete and meaningful support to the Quraish. Both the parties gave their ear and attention to what Nu'aim (RA) said to them, for his acceptance of Islam was still a secret. When the siege had lasted over 27 days, a violent windstorm uprooted the tents of the polytheists and overthrew their cooking pots. "We sent a hard gale and such an army they could not witness." (33:9)
Their fires were put out in their camps and the polytheists took it as an ill omen. The polytheists were so much overpowered by fear and frustration that they scuttled off in the darkness of night.
Allah the Almighty Himself sent to His Prophet (SAWS) the news that the bewildered polytheists had fled. Thereupon the Prophet (SAWS) sent Hudhaifah Ibn AI-Yaman (RA) to bring the news, he gave the glad tidings that the enemy departed leaving no trace behind. The Prophet (SAWS) remarked, "The Quraish shall not come at you after this year."
The Muslims returned to Al-Madinah overwhelmed with joy. This event took place in Dhul-Qa'dah, 5 AH. Ibn Umm Maktum (RA) was appointed the administrator of Al-Madinah in the absence of the Muslims. On returning to Al-Madinah, the Prophet (SAWS) halted there only for a short while and said after offering Zuhr prayer that the 'Asr prayer would be performed in the locality of Banu Quraithah. So, the Muslims proceeded on to Banu Quraithah before laying their arms aside.
From: The History of Islam, Vol.1