The Qainuqa' Jews breach the Covenant
Seeing that Allâh sided with the believers and granted them a manifest victory and perceiving the Muslims’ awesome presence in Madinah, the Jews could no longer contain themselves or conceal indignation. They started a series of provocative and harmful deeds publicly. The most wicked amongst them were the tribe of Banu Qainuqa‘, who lived in quarters within Madinah named after them. As for jobs, they took up goldsmithery, blacksmithing and crafts of making household instruments, that is why war weaponry was available in large quantities in their houses. They counted 700 warriors, and were the most daring amongst the Jewish community in Arabia, and now the first to breach the covenant of cooperation and non-aggression which they had already countersigned with the Prophet [PBUH]. Their behaviour grew too impolite and unbearable. They started a process of trouble-making, jeering at the Muslims, hurting those who frequented their bazaars, and even intimidating their women. Such things began to aggravate the general situation, so the Prophet [PBUH] gathered them in assemblage, admonished and called them to be rational, sensible and guided and cautioned against further transgression. Nevertheless they remained obdurate and paid no heed to his warning, and said: "Don’t be deluded on account of defeating some Quraishites inexperienced in the art of war. If you were to engage us in fight, you will realize that we are genuine war experts."
In this regard, the Words of Allâh were revealed saying:
The answer of Banu Qainuqa‘ amounted, as seen, to war declaration. The Prophet [PBUH] suppressed his anger and advised the Muslims to be patient and forbearing and wait for what time might reveal.
The Jews, went too far in their transgression, presumptuous behaviour and licentious practices. One day a Jewish goldsmith provoked a Muslim woman whose genitals become uncovered when he had tied the edge of the garment to her back. A Muslim man happened to be there and killed the man; the Jews retaliated by killing that Muslim. The man’s family called the Muslims for help and war started. [Ibn Hisham 2/47,48]
On Saturday, Shawwal 15th, 2 A.H., the Prophet [PBUH] marched out with his soldiers, Hamzah bin ‘Abdul Muttalib, carrying the standard of the Muslims and laid siege to the Jews’ forts for 15 days. Allâh cast fear into their hearts, and they were obliged to defer to the Messenger[pbuh]’s judgement on their lives, wealth, women and children; their hands were tied behind their backs.
At this point, ‘Abdullah bin Ubai bin Salul started his hypocritical role and began to intercede for them persistently on grounds of former alliance between those Jews and His tribe Khazraj. Muhammad [PBUH] dealt with this man as being a Muslim -- He had faked conversion into Islam for only one month, by that time -- and so he granted him his request; for Islam accepts people at their face value. Banu Qainuqa‘ handed over all materials, wealth and war equipage to the Prophet [PBUH], who set aside one fifth and distributed the rest to his men. After that they were banished out of all Arabia to Azru‘a in Syria where they stayed for a while and soon perished away.