One man among many tents

Nu'aym ibn Mas'ud had arrived with the tribes besieging Madinah, but he had also spent time with Banu Qurayzah before Islam, and they trusted him in a way they trusted no one else outside their own people.

He went to the Prophet ﷺ in secret and accepted Islam. Nobody in the besieging camp knew, and nobody in Banu Qurayzah knew either.

He asked what use he could be. He could not fight for the Muslims without exposing himself, so he was told he could say whatever would help turn the enemy back — this was a matter in which deception was permitted.

He went first to Banu Qurayzah. He told them that the Confederates were not people of the land the way Banu Qurayzah were — if the siege failed, Quraysh and Ghatafan could simply go home, and Banu Qurayzah would be left to face the Muslims alone, having already broken their treaty. He told them not to join the fighting until the Confederates handed over a number of their own men as hostages, so that Banu Qurayzah would have some guarantee they would not be abandoned.

He then went to Quraysh and Ghatafan, and told them the opposite half of the same trick: that Banu Qurayzah now regretted joining the siege, and planned to ask for hostages from among their men — not as a guarantee, but so they could hand those men over to the Muslims to make peace. He told them not to give up a single man if Qurayzah asked.

Both warnings were believed. When Banu Qurayzah did ask for hostages, exactly as he had arranged, the Confederates refused, exactly as he had arranged. Each side took the other's behaviour as proof that Nu'aym had told the truth.

The alliance never fought as one body again. Between the standoff and a storm that struck the camp around the same time, the siege collapsed and the Confederates went home.