Musnad Ahmad 27:1994

Hammad narrated to us, from Malik, from Nafi’, from Ibn Umar, who said: "The Messenger of Allah (peace and blessings of Allah be upon him) sent a military detachment toward Najd, and I was among them. We acquired many camels as spoils of war, and our shares were eleven or twelve camels each, and we were given an extra camel each as a reward (nafal)."