when the prophet (pbuh) first arrived in medinah, the jews who were living there had welcomed him. the prophet (pbuh) had returned their greeting, as he wished to be on good terms with them. an agreement was also reached between the muslims and the jews, which gave the jews the freedom to practice their religion and which also set out their rights and their duties. among these duties was that in the case of war with quraysh, the jews would fight on the side of the muslims.
despite this agreement, however, some of the jewish tribes, who resented the prophet's presence in medinah, soon began to cause trouble amongst the muslims.

they tried to set the muslim emigrants from mecca and the ansar against each other. the troublemakers were given many warnings but they continued to be a nuisance. in the end, the muslims had no choice but to drive them from medinah. a new agreement was offered those jews who remained but the trouble did not end there. one of the jewish tribes, the bani nadir plotted to murder the prophet (pbuh) but their plan was discovered and they, too, were exiled from the city. knowing that they could not defeat the muslims themselves, some of the leaders of the exiled jews secretly went to mecca to enlist the help of quraysh. knowing what the meccans would like to hear, they pretended to believe in the same things. they said that they thought that the old arab tradition was better than the teachings of the prophet muhammad (pbuh) and that they believed that the quraysh religion of worshipping many idols was better than the prophet's with only one god. then the jews told them that if all the arab tribes attacked medinah, the jews inside the city would help to defeat the prophet (pbuh) and islam once and for all.

the leaders of quraysh were pleased to hear all this and seizing on what seemed to them a very good opportunity, agreed to the plan and began to gather together a formidable army. in the meantime in medinah, only one jewish tribe, the bani quraydhah, refused to betray the muslims.

eventually the muslims learned of the preparations being made for war in mecca and of the plotting of the jews within medinah itself. the betrayal of the muslims by the jews did not surprise the prophet (pbuh), who said of them: 'the hearts of the jews have become closed to the truth. they have forgotten what moses taught them long ago that there is only one god.'
in the name of allah, the beneficent, the merciful
"the likeness of those who are entrusted with the law of moses, yet apply it not, is as the likeness of the ass carrying books.

evil is the likeness of the people who deny the revelations of allah. and allah guideth not wrongdoing folk". (koran lxii.5)
the muslims wondered how they could defend medinah. they heard that abu sufyan was coming to attack them with an enormous army which included many other arab tribes, as well as quraysh. what were they to do with only a single week to prepare? the prophet (pbuh) and his men knew that it would be impossible for them to fight off all these tribes! the only thing they could do was to stay inside the city and try to defend it as best they could. now among the people of medinah was a persian named salman, who had to live in the city some time before the prophet's arrival there. as a convert to christianity he had traveled to medinah after christian sages had told him that a prophet would be born in arabia. on arriving at madinah he was, however, sold into slavery by the merchants with whom he had traveled. later he became a muslim, gained his freedom and became a member of the prophet's household.

when the people gathered to discuss a plan of action against the approaching enemy, salman was present and it was he who suggested that they should dig a trench around the city. the prophet (pbuh) thought this a good idea, so the muslims set to work, although it was in the middle of winter. they worked day and night, digging the trench as quickly as possible. the prophet (pbuh) himself carried rocks and when the men were tired he gave them the will to carry on. someone later recalled how beautiful he looked, dressed in a red cloak with dust upon his breast and his dark hair nearly reaching his shoulders. there was little food at this time and the men were often hungry as they worked.
on one occasion, however, a little girl gave some dates to the prophet (pbuh), which he spread out on a cloth. the men were then called to eat and the dates kept increasing in number until everyone had been fed. even after everyone had eaten their fill, the dates continued to increase so that there were more than the cloth could hold.

similarly, there is the story of the lamb, that has come down to us from one who was there: 'we worked with the apostle at the trench. i had a half-grown lamb and i thought it would be a good thing to cook it for allah's messenger. i told my wife to grind barley and make some bread for us. i killed the lamb and we roasted it for the prophet (pbuh). when night fell and he was about to leave the trench, i told him we had prepared bread and meat and invited him to our home. i wanted him to come on his own, but when i said this he sent someone to call all the men to come along. everyone arrived and the food was served. he blessed it and invoked the name of allah over it. then he ate and so did all of the others. as soon as one lot were satisfied, another group came until all the diggers had eaten enough, but still there was food to spare.
on march 24, 627 a.d, abu sufyan arrived with more than ten thousand men. the muslims numbered only three thousand.

quraysh and their allies surrounded medinah but between the two armies was the long, wide trench.

the prophet (pbuh) and his men stayed behind this trench for nearly a month defending the city against their more powerful enemy. many times warriors tried to cross the trench and enter the city, but each time they were pushed back by the muslims. the muslims were afraid that if any did manage to cross over, the jews inside medinah would join forces with them and the muslims would be beaten. the jewish tribe of bani quraydhah, who had stood by the, agreement with the muslims, were pressed by a jewish emissary from the enemy, to break their promise. eventually they agreed to do so and when the news of this reached the prophet (pbuh) and his companions they were greatly troubled. sa'd ibn mu'adh, the leader of the tribe of aws, was sent by the prophet (pbuh) with two other men to find out if this were true. when they arrived in the part of medinah where the jews lived, they found that it was even worse than they had previously thought.

sa'd ibn mu'adh, whose tribe was closely allied with the bani quraydhah, tried to persuade their leader not to break the treaty with the muslims, but he refused to listen. this meant that the muslims could not relax their guard for one moment, for they were now threatened not only by the enemy beyond the trench, but by the bani qurayzah, within the walls of the city.
things became more difficult for the muslims day by day. it was extremely cold and food began to run out. to make matters worse, the bani qurayzah began openly and actively to join forces with the other jews and cut off all supplies to the muslims, including food. the enemies of islam then planned how to capture medinah.
the situation looked desperate and the prophet (pbuh) prayed to allah to help the muslims defeat their enemies. that very night a sandstorm blew up which buried the tents of quraysh. the storm continued for three days and three nights making it impossible for the enemy to light a fire to cook a meal or warm themselves by.

on one of these dark nights the prophet (pbuh) asked one of his men, hudhayfah ibn al-yaman, to go on a dangerous mission. the prophet (pbuh) told him to make his way across the trench to the enemy camp where he should find out what they were doing. with much difficulty hudhayfah crossed the trench and made his way to a circle of quraysh warriors talking in the darkness. he sat near them, but as there was no fire, no one noticed him. he then heard abu sufyan's voice: 'let us go home!' he said. 'we have had enough. the horses and camels are dying, the tents keep blowing away, most of the equipment has been lost, and we can not cook our food. there is no reason to stay!'
shortly after hearing this hudhayfah made his way quickly and quietly back across the trench and the next morning the muslims rejoiced to find that what he had overheard had come true-quraysh and their allies had gone away!

the siege of medinah had ended in a great victory for islam. but this was not to be the end of the difficulties, for the archangel gabriel the prophet (pbuh) and told him that he should punish the bani qurayzah for betraying him and the muslims.
on hearing this, the prophet (pbuh) ordered the muslims to march against the bani qurayzah as they hid in their fortress. the muslims besieged them for twenty-five days until they finally gave in. on surrendering, they asked the prophet (pbuh) to let someone judge their case, and he agreed. he also allowed them to choose who would give the ruling. the man chosen to judge the bani qurayzah was sa'd ibn mu'adh, leader of the aws, a tribe which had always protected the qurayzah in the past. sa'd ibn mu'adh who had himself been wounded in the battle, decided that the jews should be tried by their own holy law, according to which anyone who broke a treaty would be put to death. as a result all the men of the bani qurayzah were executed and the women and children made captive.

if the jews had succeeded in their pact, islam would have been destroyed. instead from that day on, medinah became a city where only muslims lived.
very soon after peace had been restored to medinah, sa'd ibn mu'adh died of his wounds. it was said that the archangel gabriel came in the middle of that night and said to the prophet (pbuh) Ɔ muhammad, who is this dead man? when he arrived, the doors of heaven opened and the throne of allah shook.' the prophet (pbuh) got up as soon as he heard this, but found that sa'd was already dead. although he had been a heavy man, the men who carried his body to the grave found it quite light. they were told that the angels were helping them. when he was buried, the prophet (pbuh) said three times 'subhan allah!' (glory be to allah!), and 'allahu akbar!' (allah is most great!). when asked why he did this, he replied, 'the grave was tight for this good man, until allah eased it for him.' this is one of the rewards that allah gives to martyrs and good muslims.