Hadith 3993
Chapter 2: The Gravity of the Sin of Shedding Blood - كتاب تحريم الدم
أَخْبَرَنَا أَحْمَدُ بْنُ سُلَيْمَانَ، قَالَ حَدَّثَنَا أَبُو دَاوُدَ، عَنْ سُفْيَانَ، عَنِ الأَعْمَشِ، عَنْ أَبِي وَائِلٍ، قَالَ قَالَ عَبْدُ اللَّهِ أَوَّلُ مَا يُقْضَى بَيْنَ النَّاسِ يَوْمَ الْقِيَامَةِ فِي الدِّمَاءِ .
It was narrated from 'Abdullah that:
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."
Reference : Sunan an-Nasa'i 3993
In-book reference : Book 37, Hadith 28