Peace said:
Read about the battle of Trench on the following link in order to know the truth about the end of Banu Qurayzah.
http://www.islamanswers.net/moreAbout/Trench.htm
Peace
Some material from Muhammad and the Course of Islam by H. M. Balyuzi:
"In the pilgrim season of A.D. 620 Muhammad focused His attention on visitors from Yathrib. This was the town where His father had died in the prime of manhood and near which he was buried. In His childhood, Aminah, His mother, had taken Him to Yathrib where she had relatives. Conditions in this town differed from those at Mecca. The existence of three strong Jewish colonies -- the Banu-Qaynuqa', the Banu'n-Nadir and the Banu-Qurayzah -- enriched the life and widened the outlook of the people, who were mostly tillers of the soil and keepers of orchards, unlike Meccans who were men of the mart and trade. They belonged in the main to two tribes, the Aws and the Khazraj, each with its own subdivisions and clans. Civil war in or around 615 had disturbed the calm of Yathrib. At the battle of Bu'ath, the Aws, with the aid of the Jewish Banu-Qurayzah and Banu'n-Nadir, had defeated the Khazraj."
(H.M. Balyuzi, Muhammad and the Course of Islam, p. 42)
"Muhammad found that the Banu-Qurayzah were justified in their complaint and gave His verdict accordingly. But the Banu'n-Nadir were resentful and considered it a deliberate affront. Huyy Ibn Akhtab, a vindictive opponent of the Prophet, dwelt with the Banu'n-Nadir and persuaded them to attempt the life of Muhammad. One day, Muhammad had gone to the settlement of this Jewish clan to carry out certain transactions. Finding Him resting against their wall, they were about to hurl down a piece of rock to crush Him, when He suddenly got up and walked away. Traditionalists say that the Angel Gabriel informed Him of their evil intent. In any case, the Banu'n-Nadir were foiled."
(H.M. Balyuzi, Muhammad and the Course of Islam, p. 87)
"Despite vigorous protests by such men as Zuhayr Ibn Bata and Yasin Ibn Qays, leading figures among the Jews of the Banu-Qurayzah, Ka'b Ibn Asad yielded to the blandishments of Huyy, decided to repudiate his pact with Muhammad, and threw in his lot with the idolaters. When Muhammad was apprised of Huyy's visit to the stronghold of the Banu-Qurayzah, He sent the two Sa'ds, one the son of Mu'adh, the head of the Aws, and the other the son of 'Ubadah, the head of the Khazraj, to warn Ka'b and counsel him not to break his word. They were accompanied by three other prominent men of the Ansar, but returned to say that the Banu-Qurayzah had gone the way of the 'Adal and the Qarih. Those clans, it will be recalled, betrayed the Muslims at ar-Raji'. The defection of the Banu-Qurayzah was not a light 97 matter. Relying on their loyalty, Muhammad had left that side of the city totally undefended. He had to find a way -- some way -- to counter whatever evil designs their chief had in mind. Would Ka'b give the besiegers a passage into Medina through his settlement? Would he mount an attack on the Muslims? These were imponderables, but for the time being it seemed that Ka'b was doing no more than seeing to his own defences.
A man of the Ghatafan, named Nu'aym Ibn Mas'ud, had been converted to Islam only a few days before the arrival of the confederate army outside Medina. Neither the Jews nor the idolaters knew this, and the Prophet accepted Nu'aym's offer to make use of this fact to cause a rift between them. Nu'aym went first to the Banu-Qurayzah; winning their confidence, he suggested that to obtain continued support from the idolaters, particularly the Meccans, and to ensure their own safety, they should ask for hostages from the Quraysh, who would not then abandon them to their fate. Then Nu'aym went to the confederate camp and warned them to be on guard against the trickery of the Jews. They would ask the Quraysh for hostages, he said, but would hand them over to Muhammad in order to ingratiate themselves with Him and avert His vengeance. In due course the Banu-Qurayzah were told to attack the Muslims on the south side of the oasis; they asked first for hostages and their demand was rejected. Mutual suspicion, engendered by Nu'aym, kept the Quraysh and the Banu-Qurayzah apart and the latter out of the war."
(H.M. Balyuzi, Muhammad and the Course of Islam, p. 96)
"Professor Montgomery Watt comments thus on the fate of the Banu-Qurayzah:
'Some European writers have criticized this sentence for what they call its savage and inhuman character . . .
'In the case of the Muslims involved in the execution what was uppermost in their minds was whether allegiance to the Islamic community was to be set above and before all other alliances and attachments... Those of the Aws who wanted leniency for Qurayzah seem to have regarded them as having been unfaithful only tb Muhammad and not to the Aws. This attitude implies that these men regarded themselves as being primarily members of the Aws (or of some clan of it) and not of the Islamic community. There is no need to suppose that Muhammad brought pressure to bear on Sa'd ibn-Mu'adh to punish Qurayzah as he did. A farsighted man like Sa'd must have realized that to allow tribal or clan allegiance to come before Islamic allegiance would lead to a renewal of the fratricidal strife from which they hoped the coming of Muhammad had delivered Medina. As he was being led into Muhammad's presence to pronounce his sentence, Sa'd is said to have made a remark to the effect that, with death not far from him, he must consider above all doing his duty to God and the Islamic community, even at the expense of former alliances.'[1]
[1 Muhammad, Prophet and Statesman, pp. 173-4.]
Professor Montgomery Watt further remarks:
'After the elimination of the Qurayzah no important clan of Jews was left in Medina, though there were probably several small groups. One Jewish merchant is named who purchased some of the women and children of Qurayzah! . . .
'The continuing presence of at least a few Jews in Medina is an argument against the view sometimes put forward by European scholars that in the second year after the Hijrah Muhammad adopted a policy of clearing all Jews out of Medina just because they were Jews, and that he carried out this policy with ever-increasing severity. It was not Muhammad's way to have policies of this 101 kind. He had a balanced view of the fundamentals of the contemporary situation and of his long-term aims, and in the light of this he moulded his day-to-day plans in accordance with the changing factors in current events. The occasions of his attacks on the first two Jewish clans were no more than occasions; but there were also deep underlying reasons. The Jews in general by their verbal criticisms of the Qur'ánic revelation were trying to undermine the foundation of the whole Islamic community; and they were also giving political support to Muhammad's enemies and to opponents such as the Hypocrites. In so far as the Jews abandoned these forms of hostile activity Muhammad allowed them to live in Medina unmolested.'[1]"
[1 ibid, pp.174-5.] 102
(H.M. Balyuzi, Muhammad and the Course of Islam, p. 100)