Mishkat al-Masabih 16 Retaliation كتاب القصاص 3

وَعَنْ عَبْدِ اللَّهِ بْنِ مَسْعُودٍ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «أَوَّلُ مَا يُقْضَى بَيْنَ النَّاسِ يَوْمَ الْقِيَامَةِ فِي الدِّمَاء»

‘Abdallah b. Mas’ud reported God’s Messenger as saying, “Shedding of blood will be the first matter about which judgment will be given on the day of resurrection.” (Bukhari and Muslim.)