Sunan an-Nasa'i #4709 · The Book of Oaths (qasamah), Retaliation and Blood Money

Sunan an-Nasa'iIt was narrated that Ibn Al-Musayyab said
Sunan an-Nasa'i · Book 45 · The Book of Oaths (qasamah), Retaliation and Blood Money
Sunan an-Nasa'i · كتاب 45 · كتاب الأيمان والقصاص والدية
"Qasamah existed during the Jahiliyyah, then the Messenger of Allah confirmed it in the case of an Ansari who was found slain in the dry well of the jews, and Ansar said: "The Jews kill our companion
أَخْبَرَنَا مُحَمَّدُ بْنُ رَافِعٍ، قَالَ حَدَّثَنَا عَبْدُ الرَّزَّاقِ، قَالَ أَنْبَأَنَا مَعْمَرٌ، عَنِ الزُّهْرِيِّ، عَنِ ابْنِ الْمُسَيَّبِ، قَالَ كَانَتِ الْقَسَامَةُ فِي الْجَاهِلِيَّةِ ثُمَّ أَقَرَّهَا رَسُولُ اللَّهِ صلى الله عليه وسلم فِي الأَنْصَارِيِّ الَّذِي وُجِدَ مَقْتُولاً فِي جُبِّ الْيَهُودِ فَقَالَتِ الأَنْصَارُ الْيَهُودُ قَتَلُوا صَاحِبَنَا ‏.‏
Reference : Sunan an-Nasa'i 4709In-book reference : Book 45, Hadith 4