Musannaf Ibn Abi Shayba 36:353

Hafs ibn Ghiyath narrated to us, from Muhammad ibn Zayd, who said: Umayr, the freed slave of Abi al-Lahm, narrated to me. He said: I witnessed Khaybar while I was an owned slave. When they conquered it, the Messenger of Allah (peace and blessings of Allah be upon him) gave me a sword and said, "Gird this on." And he gave me some of the miscellaneous goods, but he did not assign me a share (of the spoils).