Sunan an-Nasa'i 3995
سنن النسائي#3995SahihIt was narrated that 'Amr bin Shurahbil said:"The Messenger of Allah [SAW] said: 'The first matter concerning which scores will be settled among the people on the Day of Resurrection will be bloodshed
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih Lighairihi
Al-AlbaniSahih
Zubair Ali ZaiSahih
In-book reference: 37:30