Had God not decreed to banish them, He would have punished them in this life. In the Hereafter they will face the retribution of the fire.
Translation endnotes
[59:2-6] According to hadith books, there were three Jewish tribes in Yathrib: Banu Qaynuqa, Banu al-Nadir and Banu Qurayza. They provoked muslims and the first two tribes were forced to leave the city with their transportable possessions. However, prophet Muhammed allegedly did not forgive Banu Qurayza; their necks were struck and their children were made slaves. Estimates of those killed vary from 400 to 900. The Quran refers to the event and contrary to the claims of hearsay collections, never mentions killing or enslaving them, which is in direct contradiction to many verses of the Quran. The Quran, in these verses, informs us that a group from "The People of the Book" was forced to leave the territory because of their violation of the constitution and secretly organizing war together with their enemies against muslims (59:1-4). Verse 59:3 clearly states that they were not penalized further in this world. The credibility of the story of Muhammed massacring Bani Qurayza Jews has been a controversial subject since the time it was published by Ibn Ishaq. Ibn Ishaq, who died in 151 A.H., that is 145 years after the event in question, was severely criticized by his peers for relying on highly exaggerated Jewish stories. He was also harshly criticized for presenting forged poetry attributed to famous poets. Some of his contemporary scholars, such as Malik, called him "a liar." However, his work was later copied by others without critical examination. This is an example of hearsay used by dubious Jewish reporters for propaganda purposes. Modern scholars found astonishing similarities between Ibn Ishaq and the account of historian Josephus regarding King Alexander, who ruled in Jerusalem before Herod the Great, hung upon crosses 800 Jewish captives, and slaughtered their wives and children before their eyes. Many other similarities in the details of the story of Banu Qurayza and the event reported by Josephus are compelling. Besides, the lack of reference or justification in the Quran for such a massacre of great magnitude, and the verses instructing principles for muslims to abide by removes all credibility from this story (35:18: 61:4). The Quran gives utmost importance to human life (5:32) and considers racism and anti-Semitism evil (49:11-13).