Soon after the battle of Uhud Bani Asad started making preparations for a raid on Madinah. The Prophet sent an army of 150 warriors under the command of Sayyidunã Abu Salmah (the first husband of Sayyidah Umme Salmah). This army took Bani Asad by surprise and made them run in a panic leaving all their possessions behind. After this, Bani An-Nadhir, a Jewish tribe, plotted to kill the Prophet but their plot was discovered in time. The Prophet ordered them to leave Madinah within ten days and warned that anyone who remained behind after that would be put to death. Abdullah bin Ubayy, the chief of the hypocrites of Madinah, encouraged them to defy the order and refuse to leave Madinah. He even promised to help them with 2,000 men, and assured them that the Bani Ghatfãn from Najd also would come to their aid. As a result, Bani An-Nadhir refused to follow the order and said that they would not leave Madinah no matter what. As soon as the time limit of ten days came to an end, the Prophet laid siege to their quarters, but none of their supporters had the courage to come to their rescue. At last, they surrendered on condition that every three of them would be allowed to load a camel with whatever they could carry and go away leaving the rest of their possessions behind. Thus, the entire suburbs of the city, which were inhabited by the Bani An-Nadhir, their gardens, their fortresses and other properties fell into the hands of Muslims.

After this, the Prophet received information that the tribe of Bani Ghatfãn was preparing for a war against Madinah. He marched against them with 400 Muslims and overtook them by surprise. As a result, they fled their houses without any struggle and took refuge in the mountains.

After this in the month of Sh’abãn A. H. 4, the Prophet went to the place of Badr with 1500 Muslims to fight against Abu Sufyãn, who had challenged the Prophet and the Muslims at the end of the Battle of Uhud, saying: “We shall again meet you in combat at Badr next year.” The Prophet accepted his challenge. From the other side, Abu Sufyãn left Makkah with an army of 2,000 men, but did not have the courage to march beyond the town of Marr-Az-Zahrãn, now known as Wadi Fãtimah. The Prophet waited for him at Badr for eight days; the Muslims during these days did profitable business with a trading caravan. This incident helped in restoring the image of the Muslims that had been tarnished at Uhud. It also made the whole of Arabia realize that the Qureysh alone could no longer resist Muhammad (pbuh).
 

The leaders of the Bani an-Nadhir, who had settled in Khayber after their banishment from Madinah, went around to the Qureysh, Ghatfãn, Hudhail and many other tribes requesting them to gather all their forces and attack Madinah jointly. Thus, in Shawwãl, A. H. 5, a very large army of the Arab tribes marched against the small city of Madinah. From the north came the Jews of Bani an-Nadir and Bani Qainuqah. From the east advanced the tribes of Ghatfãn, Bani Sulaima, Fazarah, Murrah, Ashja, S‘ad, Asad, etc. and from the south the Qureysh along with a large force of their allies numbering from ten to twelve thousand warriors. Had it been a sudden attack, it would have been disastrous. Before the enemy could reach Al-Madinah, the Prophet got a trench dug on the northwest of Madinah in six days and took up defensive positions with 3,000 warriors. Mount Salat was at their back, and thick palm tree gardens on their south, therefore, the enemy could not attack from those sides. The same was the case on the east side where there were lava rocks which were impassable for a large army to cross. The same was the case with the south- western side. The attack, therefore, could be made only from the eastern and western sides of the Uhud mountain, which the Prophet had secured by digging a trench. The disbelievers were not at all aware that they would have to encounter a trench outside Madinah. This kind of a defensive stratagem was unknown to the Arabs. Thus, they had to lay a long siege during winter for which they were not prepared.

The only alternative that remained for the disbelievers was to incite the Jewish tribe of Bani Quraizah, who were living in the southeastern part of the city to rebel. The Prophet had a treaty with them that in case of an attack on Madinah they would defend the city along with them. As a result, the Prophet had made no defensive arrangement in that area and had even sent Muslim families to take shelter in the forts situated on that side of the city. The invaders perceived this weakness in the defenses of the Muslim army. They sent a Jewish leader of Bani An-Nadhir to Bani Quraizah and induced them to break the treaty and join the war against the Muslims. In the beginning, they refused saying that they had a treaty with Muhammad (pbuh) who had faithfully abided by it and given them no cause for complaint. But, when Ibn Akhtab said to them, “Look, I have summoned a united force of entire Arabia against him. This is a perfect opportunity to get rid of him, if you lose it, you will never have another opportunity,” thus, the anti-Islamic mind prevailed over every moral consideration and they agreed to violate the treaty.

When the Prophet received this news, he at once asked the chiefs of the Ansãr, to go and find out the truth. He advised them that if they found Bani Quraizah still loyal to the treaty, they should return and say so openly before the Muslim army; however, if they found that they were bent upon treachery, they should only inform him so that the common Muslims would not panic. When inquired, Bani Quraizah openly told the chiefs: “There is no agreement and no treaty between us and Muhammad.” At this they returned and submitted their report to the Prophet.

After ascertaining verification, the Prophet, at that critical moment, initiated peace negotiations with the warrior tribe of Bani Ghatfãn offering them one third of the fruit harvest of Madinah in lieu of their withdrawal. But when he asked S‘ad bin Ubãdah and S‘ad bin Muãdh, chiefs of the Ansãr for their opinion about the conditions of peace, they asked, “O Rasool of Allah: Is it your personal wish that we should agree on these conditions, or is it Allah’s Command that we have no option but to accept it, or, are you proposing this only to save us from the enemy?” The Prophet replied, “I am proposing this only to save you: I see that the whole of Arabia has formed a united front against you. I want to divide the enemy.” At this, the two chiefs protested saying, “Your honor, if you want to conclude this pact for our sake, please forget it. These tribes could not subdue us under tribute when we were polytheists. Now that we have the honor of believing in Allah and His Rasool, will they make us sink to this depth of ignominy? Let the sword be the arbiter till Allah passes His judgement between them and us.” With these words, they tore up the draft for the treaty which had not yet been signed.

In the meantime Nu‘aim bin Mas‘ud, a member of the Ashja branch of the Ghatfãn tribe, became a Muslim and came before the Prophet and submitted, “No one as yet knows that I have embraced Islam: You can take from me whatever service you please.” The Holy Prophet replied: “Go and sow the seeds of discord among the enemy.” So, first of all, Nu‘aim went to the tribe of Quraizah with whom he was on friendly terms, and said to them, “The Qureysh and the Ghatfãn can become wearied of the siege and go back, and they will lose nothing, but you have to live here with the Muslims. Just consider what your position will be if the matter turns out that way. Therefore, I would advise you not to join the enemy until the outsiders should send some of their prominent men as hostages to you.” This had the desired effect upon the Bani Quraizah and they decided to demand hostages from the united front of the tribes. Then he went to the chiefs of the Qureysh and the Ghatfãn and said to them, “The Bani Quraizah seem to be slack and irresolute. They may demand some men as hostages from you and then hand them over to Muhammad (upon whom be Allah’s peace) to settle their affair with him. Therefore, be very firm and cautious in your dealing with them.” This made the leaders of the united front suspicious of Bani Quraizah, and they sent them a message, saying, “We are tired of the long siege; let there be a decisive battle; let us, therefore, make a general assault simultaneously from both the sides.” The Bani Quraizah sent back the word, saying, “We cannot afford to join the war unless you hand over some of your prominent men to us as hostages.” The leaders of the united front became convinced that what Nu‘aim had said was true. They refused to send hostages. And the Bani Quraizah, on the other side, also felt that Nu‘aim had given them the correct counsel. Thus, the strategy worked: it divided the enemy against itself.

The siege was prolonged for more than 25 days. It was winter, and supply of food and water and forage was becoming more and more scarce. Division in the camp was also a great strain on the state of morale of the besiegers. Then, suddenly one night, a severe windstorm accompanied by thunder and lightning hit the camp. It added to the cold and darkness. The wind blew over the tents and put the enemy in disarray. They could not withstand this severe blow of nature. They left the battleground during the night and returned to their homes. When the Muslims awoke in the morning, there was not a single enemy soldier to be seen on the battlefield. The Prophet, finding the battlefield completely empty, said: “The Qureysh will never be able to attack you after this: now you will take the offensive.” This was a correct assessment of the situation. Not only the Qureysh but the united front of all the enemy tribes had made their final assault against Islam and had failed. Now they could no longer dare invade Madinah; now the Muslims were on the offensive.
 

When the Prophet returned from the Trench, angel Gabriel came to him in the early afternoon with the Divine Command; the Muslims should not lay aside their arms without dealing with the Bani Quraizah. On receipt of this Command, the Prophet made the announcement: “Everyone who is steadfast in obedience should not offer his 'Asr Prayer till he reaches the locality of the Bani Quraizah.” Immediately after this, he despatched Sayyidunã Ali with a contingent of soldiers as vanguard towards the Quraizah. When they reached there, the Jews climbed on to their roof tops and started hurling abuses on the Prophet and the Muslims, but their invectives could not save them from the consequences of their treachery. They had committed a breach of the treaty at the most critical moment of the war, joined hands with the invaders and endangered the entire population of Madinah. When they saw the contingent of Sayyidunã Ali, they thought that they had come only to overawe them. But when the whole Muslim army arrived under the command of the Prophet himself and laid siege to their quarters, they were very frightened. They could not stand the severity of the siege for more than two or three weeks. At last,they surrendered themselves to the Prophet on the condition that they would accept whatever decision Sayyidunã S‘ad bin Muãdh, the chief of the Aus, would give. They had accepted Sayyidunã S‘ad as their judge because, in the pre-Islamic days, the Aus and the Quraizah had been confederates. They hoped that in view of their past ties, the people of the Aus also wished that Sayyidunã S‘ad would treat their previous allies leniently. But Sayyidunã S‘ad had just experienced and seen how the two Jewish tribes, who had been allowed to leave Madinah previously, had instigated the other tribes living around Madinah and summoned a united front of ten to twelve thousand men against the Muslims. He was also aware how treacherously this Jewish tribe had behaved on the occasion when the city was under attack threatening the safety of its entire population. He, therefore, decreed that all the male members of the Quraizah should be put to death, their women and children taken prisoners and their properties distributed among the Muslims. The sentence was carried out. When the Muslims entered their strongholds they found that this treacherous tribe had collected 1,500 swords, 300 coats of mail, 2,000 spears and 1,500 shields in order to join the war. If Allah had not helped the Muslims, all this military equipment would have been used to attack Madinah from the rear at a time when the polytheists were making preparations for a general assault on the Muslims after crossing the Trench. After this disclosure, there remained no doubt that the decision of Sayyidunã S‘ad concerning those people, was perfactly the right decision.

In this Sürah, the Islamic laws pertaining to marriage and divorce were complemented; the law of inheritance was introduced, drinking and gambling were prohibited, and new laws and regulations concerning economic and social life were enacted.
 

The question concerning adoption was also addressed in this Sürah. An adopted son was regarded as their own offspring by the Arabs at that time: he was entitled to inheritance; he was treated like a real son and real brother by the adopted mother and the adopted sister; he could not marry the daughter of his adopted father or his widow after his father's death. And the same was the case if the adopted son died or divorced a wife. The adopted father regarded the woman as his real daughter-in-law. This custom clashed in every detail with the laws of marriage and divorce and inheritance enjoined by Allah in Sürahs Al-Al-Baqrah and An-Nisã'. It made a person who could get no share in inheritance, entitled to it at the expense of those who were really entitled to it. It prohibited marriage between the men and the women who could enter into the contract of marriage. And, above all, it helped spread the immoralities which the Islamic Law wanted to eradicate. For a real mother, a real sister and a real daughter cannot be like the adopted mother, the adopted sister and the adopted daughter. When artificial relations endowed with customary sanctity are allowed to mix freely like the blood relations, evil is often the result. That is why the Islamic law of marriage and divorce, the law of inheritance and the law prohibiting adultery require that the concept and custom of regarding the adopted son as a real son should be eradicated. This concept however could not be uprooted by merely passing a legal order because centuries old prejudices and superstitions could not be changed by mere word of mouth. Therefore, a little before the Battle of the Trench, the Prophet was asked by Allah to marry Sayyidah Zainab, the divorced wife of his adopted son, Zaid bin Hãrithah (may Allah be pleased with him). The Holy Prophet acted on this Commandment during the siege of Bani Quraizah.
 

As soon as the marriage was contracted, there arose a storm of propaganda against the Prophet. The polytheists, the hypocrites and the Jews all were burning with jealousy at the Prophet's triumphs which followed one after the other. The way they had been humbled within two years after Uhud, in the Battle of the Trench, and in the affair of the Quraizah, had made them sore at heart. They had also lost hope that they could ever subdue him on the battlefield. Therefore, they seized the question of this marriage as a godsend blessing for them and thought they would put an end to his moral superiority, which was the secret of his power and success. Therefore, stories were concocted that Muhammad, God forbid, had fallen in love with his daughter-in-law, and when his son had come to know of this, he divorced his wife, and the father married his daughter-in-law. The propaganda, however, was absurd on the face of it. Sayyidah Zainab was the Prophet’s first cousin. He had known her from childhood to youth. So, there could be no question of his falling in love with her at first sight. Then he himself had arranged her marriage with Sayyidunã Zaid under his personal influence, although her whole family had opposed it. They did not like that a daughter of the noble Qureysh should be given in marriage to a freed slave. Sayyidah Zainab herself was not happy at this arrangement. But everyone had to submit to the Prophet’s command. The marriage was solemnized and a precedent was set in Arabia that Islam had raised a freed slave to the status of the Qureyshite nobility. If the Prophet had in reality any desire for Sayyidah Zainab, there was no need in marrying her to Sayyidunã Zaid. He himself could have married her.