Ibn Mas'ud (May Allah be pleased with him) reported:
The Prophet (ﷺ) said, "The first matter concerning which people will be judged on the Day of Resurrection will be the matter of blood."[Al-Bukhari and Muslim]
وعن ابن مسعود رضي الله عنه قال: قال النبي صلى الله عليه وسلم :
"أول ما يقضى بين الناس يوم القيامة في الدماء"
((متفق عليه)).