Musnad Ahmad 761:2

Ya'qub narrated to us, my father narrated to us, from Salih. Ibn Shihab said: The nephew of Abu Ruhm al-Ghifari informed me that he heard Abu Ruhm—and he was one of the companions of the Messenger of Allah, peace and blessings of Allah be upon him, who pledged allegiance under the tree—saying: I went on the expedition of Tabuk with the Messenger of Allah, peace and blessings of Allah be upon him, and I slept one night at al-Akhsar. I traveled near him, and he mentioned the meaning of the hadith of Ma'mar, except that he said: So I began to hold back my riding beast until my eyes overcame me for part of the night. And he said: "What have the black, curly-haired, short people done, who have livestock at Shaziyat Sharkh?" And he thought they were from the tribe of Ghifar.