Musannaf Ibn Abi Shayba 36:282

Abdullah ibn Idris narrated to us, from Abu Ma'shar, who said: Al-Harith ibn 'Awf and 'Uyaynah ibn Hisn came to the Messenger of Allah (may Allah bless him and grant him peace) during the year of the Trench and said, "We will hold back Ghatafan from you on the condition that you give us the fruits of Medina." He said: They negotiated with him until the matter was settled on half of the fruits of Medina. They said, "Write a document between us and you." So he called for a parchment. He said: And the two Sa'ds, Sa'd ibn Mu'adh and Sa'd ibn 'Ubadah, were sitting there. They turned to the Messenger of Allah (may Allah bless him and grant him peace) and said, "Is this something that has come to you from Allah, which we have no right to oppose?" He said, "No, but I wanted to turn the faces of these people away from me, so that my attention could be devoted to these others." He said: They said to him, "The Arabs never attained anything from us during our Jahiliyyah except through purchase or hospitality."