It was narrated from Abdullah that the Messenger of Allah (ﷺ) said:
"The first matter concerning which judgment will be passed among the people on the Day of Resurrection will be bloodshed." (JA)
English reference (JA): Vol. 3, Book 21, Hadith 2615 (JA)
Arabic reference (JA): Book 21, Hadith 2713 (JA)