Musannaf Ibn Abi Shayba 36:421

Abu Mu'awiyah narrated to us, from al-Hajjaj, from al-Hakam, from Miqsam, from Ibn Abbas, who said: The Messenger of Allah (may Allah bless him and grant him peace) freed, on the day of Ta'if, everyone who came out to him from the slaves of the polytheists.