(2) باب الْقَسَامَةِ
it was narrated from Abu Salamah and Sulaiman bin Yasar, from some of the Companions of the Messenger of Allah, that:
Qasamah existed during the Jahiliyyah and the Messenger of Allah approved of it as it had been during the Jahiliyyah, and he ruled accordingly among some of the Ansar concerning a victim whom they claimed the Jews of Khaibar had Killed. (Sahih)Ma'mar contradicted the two of them.
Reference: Sunan an-Nasa'i 4708
In-book reference: Book 45, Hadith 3
English translation: Vol. 5, Book 45, Hadith 4712