Musannaf Ibn Abi Shayba 36:276

Yazid ibn Harun narrated to us, he said: Hammad ibn Salamah informed us, from Hisham, from his father, who said: There was a man among the companions of the Messenger of Allah, may Allah bless him and grant him peace, who was called Mas'ud, and he was a tale-bearer. When the day of the Trench arrived, the people of Qurayza sent to Abu Sufyan, "Send to us men who will be in our fortresses so that we may fight Muhammad from the side of the city, and you fight from the side of the Trench." This was difficult for the Prophet, may Allah bless him and grant him peace, that he should be fought from two directions. So he said to Mas'ud, "O Mas'ud, we have sent to Banu Qurayza to send [a message] to Abu Sufyan to send men to them, and when they come to them, they will kill them." He said: No sooner had he heard that from the Prophet, may Allah bless him and grant him peace, than he could not restrain himself until he went to Abu Sufyan and informed him. He [Abu Sufyan] said, "By Allah, Muhammad has spoken the truth; he has never lied." So he did not send anyone to them.