The Messenger of Allah ﷺ said, "The first matters to be judged among people on the Day of Resurrection will be those concerning bloodshed."
قال رسول الله ﷺ: أول ما يقضى بين الناس يوم القيامة في الدماء.
Bukhari narrated it in Riqaq (6533), and Muslim in Qasamah (28:1678), both through Amash, from Shaqiq Abu Waail, from Abdullah, and he mentioned it.