Musnad Ahmad 333:14

Qaran ibn Tamam narrated to us, from Ikrimah al-Yamami, from Iyas ibn Salamah, from his father, who said: "I went out with Abu Bakr on the expedition of Hawazin, and he gave me a slave girl as a share of the spoils (nafal). Then the Messenger of Allah, peace and blessings of Allah be upon him, asked me for her as a gift, so I gave her to him. He then sent her to Makkah and ransomed with her some people among the Muslims."