Musannaf Ibn Abi Shaybah 39580 — The Battle of the Trench

Hisham narrates from his father that among the companions of the Messenger of Allah (peace and blessings be upon him) was a man called "Mas'ud." He was much given to talebearing. On the day of the Trench, Banu Qurayzah sent a message to Abu Sufyan: "Send us some men to be (stationed) in our fortresses, so that we can fight Muhammad from the (inner) side of Madinah, and you can fight from the side of the Trench." He (peace and blessings be upon him) found fighting on two sides difficult. He (peace and blessings be upon him) said to Mas'ud: "O Mas'ud! We have sent a message to Banu Qurayzah that they should send to Abu Sufyan for his men, and when Abu Sufyan sends his men to them, Banu Qurayzah will kill them." When Mas'ud heard this, he could not restrain himself and he went and told Abu Sufyan. Abu Sufyan said: "By Allah, Muhammad has always told the truth and has never lied." So he did not send anyone to Banu Qurayzah. (This action of the Prophet, peace and blessings be upon him, was part of a stratagem of war.)