When Rasulullah came to Madinah, he signed a treaty (agreement) with the Jews to live in peace and harmony and help each other against anyone who wanted to attack Madinah. The Jews contravened (broke) the treaty and conspired (made plans) with the Quraish of Makkah, the Munafiqs and other enemies of Islaam to bring to an end the mission of Rasulullah .
ordered the Banu Qainuqah out of Madinah and they went and settled in Syria.
Then the Banu Nadhir were ordered to leave Madinah. They refused to make
a new agreement and they attempted to assassinate Rasulullah .
Some of the Banu Nadir clan settled in Khaibar while others went and settled
in Syria. All this happened in the 4th year of Hijrat. In the year 5 Hijrat
the Banu Quraizah joined the kuffar against the Muslims in the Battle of
Ahzab. After a siege (blockade) of one month they (the Banu Quraizah) gave
up and requested that Hazrat Sa'ad bin Mu'az (R.A.) be asked to decide
what should be done with them. In passing judgment Hazrat Sa'ad bin Mu'az
(R.A.) ordered that the able bodies and active fighters be put to death,
the women and children to be treated as prisoners of war and their goods
and property to be handed over as spoils of war to be distributed among
the poor Muslim workers. This decision was compatible with the commands
of the Taura (The Book of the Jews),
Contents of the biography of the Prophet Muhammed