The settlement of Khyber was 95 miles from Medina and a stronghold of the Arab Jews. It consisted of nine or ten Jewish forts. At Khyber, various pagan Arab tribes that opposed the Prophet (sw) were also given refuge by the Jews. Khyber stayed an active center of conspiracies against the Muslims in Medina for almost two years. It was on the 7th year of the Hijrah that the Prophet (sw) was left with no other choice but to confront this source of aggression.
Battle of the Trench (Ghazwa-e-Khandaq) was fought on 5th Hijrah, two years prior to the battle in Khyber. By this time the Jewish tribe of Banu Nadir had already been expelled from Medina for its continuous role as a trouble maker, many of whose adherents had settled in Khyber. Banu Qunaika (or Kanuka as in Hebrew) was expelled for its declaration of war on the Prophet (sw) after the Battle of Badr which took place on 3rd Hijrah. It's recounted that some adherents of Banu Qunaika settled in Wadi-e-Kura, north of Medina and some went to Syria. But in reality, many of them landed up in Khyber. Khyber also became the destination of several members of the tribe of Banu Qurayza after their defeat in the Battle of Trench in 5th Hijrah.
That common story about the "massacre of Banu Qurayza" after Battle of the Trench is one of the biggest fairy tales in world history. Unfortunately, like many orientalists, even some Muslim historians like Ibn Ishaq and Ibn Khalidun have used this fabrication in their works.
Evidence from the Glorious Quran
Referring to the Sole Criterion, the Noble Quran, Verses 33:26, there is absolutely NO indication of 'mass killing' of Banu Qurayza.
"And He brought those of the People of the Scripture who supported them down from their strongholds, and cast panic into their hearts. Some ye slew, and ye made captive some." (33:26)
Verse 33:26 is a reference to the treachery of Banu Qurayza and when the Muslim army confronted them after the Battle of the Trench. Mark the words of Verse 33:26 - "some ye slew, and ye made captive some." This clearly denotes few people being killed in the battle and few being taken as prisoners. It includes only those who were on the frontline of the battle. A massacre is never described in this manner. In particular, the language and style of the Noble Quran is so articulate that whichever event is described, whether briefly or in detail, is very vividly and coherently expressed with no scope of any misunderstandings. The expression mentioning the casualties of Banu Qurayza in Verse 33:26 by no means indicates execution-style killing of the entire tribe. That's crystal clear.
This Jewish tribe showed open treachery during the Battle of the Trench. After the battle when Qureysh along with various pagan clans had deserted the battlefield, the Muslims faced up to deal with Banu Qurayza who were in their Jewish stronghold of Medina. Whatever casualties took place was during the fight between the Muslims and the adherents of Banu Qurayza. This is precisely what the Quran defines in the above mentioned Verse. As we can see, the allusion to the confrontation between the Muslims and Banu Qurayza in the Quran is brief and there is no reference whatsoever to any mass slaughter even in the remotest sense. The Quran refers to it in a battle context, to those who were actually fighting. The Quran is the only authority to be accepted without hesitation or doubt.
The rule in Islam is to punish only those who were responsible for the sedition. To kill such a large number is the exact opposite of the Islamic sense of justice and opposite to the important principles of the Qur'an - particularly the verse "That no laden one shall bear another's load," (53:38).
The version of all women
Many historical data conform with information contained in the Glorious Quran (V.33:26)
Many history books recounting the story of Qurayza have stated that a few specific persons were named during the event as having been put to death, some of whom were described as particularly active in their hostility. It is the reasonable conclusion that those were the ones who led the sedition and who were consequently punished - NOT the whole tribe.
The myth of Banu Qurayza is inconsistent compared to the decisions of Muslims concerning Banu Nadir and Qunaika
It is unlikely, if not impossible, that the Banu Qurayza should be slaughtered when the other Jewish tribes of Banu Nadir and Qunaika which had surrendered earlier were treated leniently and allowed to go for the same crime. Abu Ubayd Salam relates in his Kitab al-amwal the final words of the Prophet (sw) to Banu Qurayza: "I have known the extent of your hostility to God and to His apostle, yet that does not prevent me from treating you as I treated your brethren." This is reported as the Prophet's response after the surrender of Banu Qurayzah.
No tangible historical evidence of such an incident
Had this slaughter actually happened and if so many hundreds of people had actually been put to death in the "market-place" (as babbled in the fabricated stories and forged ahadith), it's very strange and unusual that there was never any trace of mass graves nor any sites of mass burial anywhere in Medina, even though many other important historical landmarks were preserved for a long time, some are present even now. But absolutely nothing to indicate that an entire tribe had been executed and buried at any particular spot or scattered spots in Medina.
No evidence of Saad bin Muad being told to decide the fate of Banu Qurayza other than forged narrations
Just as the descendants of Banu Qurayza would want to glorify their ancestors, so did the descendants of Saad bin Muad, the chief of Aus tribe of Medina whose adherent was Banu Qurayza. According to the myth, the Prophet (pbuh) requested Saad bin Muad to make a decision about the fate of Banu Qurayza. Later, evidence emerged that that part of the story which claims all men of Banu Qurayza were put to death and women and children taken prisoners was transmitted from one of Saad's direct descendants with no evidence that the Prophet at all approached Saad to decide about Banu Qurayza. In other words, this account from one of Saad's descendents is exactly as unreliable, rather utterly false, as 99.9% of the fabricated Ahadith we have read.
Senseless gossips only expose this myth still more
As usual, lots of illogical narrations from irrelevant personalities have come up, hurling one falsehood upon another concerning the Banu Qurayza story. For example, one historical narration claims that all prisoners of Banu Qurayza were incarcerated in the house of a woman from Banu al-Najjar. No one even knows who this woman was nor does this Arab tribe of Banu al-Najjar have any significance in Islamic History. Moreover, how could so many hundreds of prisoners be accommodated in a common house belonging to a woman of Banu al-Najjar? Just doesn't make sense.
Gossip mongering by Arab Jews a prime factor for distortions, creation of this tale and confusion among historians
The blatant fact of the matter is that stories regarding the Arab Jews have been distorted and manipulated grossly by their descendants until almost 200 years after the passing away of the Prophet (sw). Regarding the unacceptable story of the slaughter of Banu Qurayza, the real source of this myth was the descendants of the Jews of Medinah, from whom Ibn Ishaq took these "odd tales". For doing so Ibn Ishaq was severely criticized by other scholars and historians within the circle of the traditionalists themselves. Ibn Ishaq was called "an impostor" by Malik.
What is being confused or intentionally distorted by various historians is the inside story coming directly from the Jews of Banu Qurayza in the words of their leader, Kaab bin Asad, who in his lengthy and aggressive speech is reported to have suggested that Banu Qurayza should eliminate their women and children and make a last desperate attempt against the Muslim army. It's interesting to note that according to the information contained in several episodes of history, an ancient and frantic Jewish tradition in times of complete despair and distress was mass suicide. That tallies with the report in some history books about Kaab bin Asad's intentions in his long and aggressive speech. However, another historical version suggests that many Jews of Banu Qurayza refused to commit suicide, giving further evidence that NO mass death was inflicted upon the Jews, neither by the Muslims nor by themselves. It also explains how scores of adherents of Banu Qurayza were later found to have joined the Jewish stronghold at Khyber, giving still greater credence to the fact that after the Battle of the Trench, the tribe of Banu Qurayza was expelled from Medina and NOT executed en masse.
False Ahadith only strengthened the falsified version of the Banu Qurayza story
When the culture of Hadith narrations began in full swing during the reign of the Ummayads, a lot of those young so-called sahabas who had never even met or seen the Prophet (sw) began narrating tons of fabrications. Several of them who converted to Islam were Jews or Christians. They were brazen opportunists with no sincere attachments to Faith. They forged plenty of narrations that were discreetly supportive of the Jewish tribes of Arabia.
The siege of Masada used as a prototype for concocting the Banu Qurayza story by medieval Arab Jews
Frankly, if you search the annals of history, you will find that circulation of such falsehoods and motivated exaggerations are quite common from Jewish sources. For example, similar unsupported stories of atrocities by Romans in 73 AD during the destruction of temple mount have been recounted by the Jewish descendants of those who lived at that time but without a shred of evidence.
A lot of Jewish history comes through the stories of the 1st century Jewish historian/priest, Flavius Josephus. He belonged to Greece but lived in Jerusalem. He has particularly mentioned a lot about the first Jewish-Roman war that resulted in the destruction of temple mount known as the "siege of Masada." Masada was the name of a place situated in the South of what's today known as Israel. This is the place where the first Jewish-Roman war began in the 1st century. The event of the siege of Masada itself, as reported by Josephus, is supposed to be full of inaccuracies. Which portions of it might conform with the truth is only known to Allah Almighty. Although Josephus was aware of many unethical actions of the Jewish rebels, he covered them up by giving plenty of wrong accounts of the actual event. If you read his works carefully, you will find that his writings and cover-ups (devoid of evidences) are very similar to the false narrations and accounts coming from Jewish sources about Banu Qurayza. For example: According to Josephus, the well known "siege of Masada" by the Romans led to mass suicide of many Jewish rebels known as "sicarii," a large segment of hardline extremist Jews. The history of Masada also mentions that when the Jewish rebels reached a point of despair, their leader, Eleazar, addressed them (just as Kaab b. Asad addressed the Banu Qurayza) suggesting that they kill their women and children. Later, when they came to a point of complete despair, they planned to kill each other. Probably this was Josephus' notion of painting the "sicarii" as 'courageous.' Historical evidence? None. Clearly, the story of Masada is strikingly similar to the story of Banu Qurayza, except that the Muslims of Medina have been made falsely responsible for the deaths of these Jews.
Another example: According to Josephus, when Alexander ruled Jerusalem, he hung 800 Jewish prisoners upon the crosses and slaughtered their wives and children before them. Historical evidence? Again, none. Sounds awfully similar to the fabrication of the story of Banu Qurayza.
The story of the siege of Masada seems to have served as a prototype, based on which other similar stories have been constructed by the Jews of later times .. the story of Banu Qurayza being one of them.
Many modern analysts and historians have opined that in the early days a certain version of the myth of Banu Qurazya was cooked up and preserved by the descendants of Banu Qurayza. Then, the later generations of the Jewish descendants of Banu Qurayza superimposed the details of the siege of Masada on the already fabricated story of the siege of Banu Qurayza, perhaps through confusion but more likely intentionally - in other words, medieval Jewish propaganda. Ibn Ishaq took this story without bothering to verify any of the details and several other historians borrowed, what appeared as Ibn Ishaq's version of the Banu Qurayza story.