The Prophet ﷺ said, "The passing away of this world is of less consequence to Allah than the killing of a Muslim man."
أخبرنا يحيى بن حكيم البصري قال حدثنا ابن أبي عدي عن شعبة عن يعلى بن عطاء عن أبيه
عن النبي ﷺ قال لزوال الدنيا أهون عند الله من قتل رجل مسلم
[Hasan] Tirmidhi transmitted it, in the Book of Blood Money, Chapter on the Severity of Killing a Believer, Hadith 1395, from the hadith of Muhammad bin Abu Adi through this route, and it is also in al-Kubra, Hadith 3449. Atta Amiri Taifi was deemed reliable by Ibn Hibban, and his hadith has corroborating narrations.