"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.'" (Using translation from Nasāʾī 3995)
قَالَ رَسُولُ اللهِ ﷺ «أَوَّلُ مَا يُقْضَى فِيهِ بَيْنَ النَّاسِ يَوْمَ الْقِيَامَةِ فِي الدِّمَاءِ»