I was present at Khaybar with my masters, and they spoke to the Messenger of Allah ﷺ about me, mentioning that I was a slave. He ordered that I be given a sword to wear, but I found myself dragging it along the ground. He then ordered that I be given some humble household goods.I also presented to him an incantation I used to recite over those afflicted with madness, and he instructed me to discard part of it and retain the rest.
حدثنا قتيبة حدثنا بشر بن المفضل عن محمد بن زيد
شهدت خيبر مع سادتي فكلموا في رسول الله ﷺ وكلموه أني مملوك قال فأمر بي فقلدت السيف فإذا أنا أجره فأمر لي بشيء من خرثي المتاع وعرضت عليه رقية كنت أرقي بها المجانين فأمرني بطرح بعضها وحبس بعضها
Its isnad is sahih. Abu Dawud narrated it in the Book of Jihad, chapter on giving women and slaves a share of the spoils, hadith 2730, from the hadith of Bishr bin Mufaddal, through the same route. Ibn Hibban graded it sahih, hadith 1669, as did Hakim, 2/131, and Dhahabi.There is also a narration on this subject from Ibn Abbas [previously mentioned, 1556].