Riyad as-Salihin, Book 19, Hadith 1845 (In-Book) ⓘ
Ibn Mas'ud (May Allah be pleased with him) reported: The Prophet 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)).