Sayyiduna Abu Bakr (may Allah be pleased with him) reports this saying of the Prophet (peace and blessings be upon him): "When a Muslim raises a weapon against his brother, the angels of Allah Almighty continue to curse him until he turns it away from (his brother) and sheathes it."
Al-Bazzar recorded it; its chain contains Suwayd bin Ibrahim, whom al-Nasa'i (may Allah have mercy on him) declared da'if (weak) and Abu Zur'ah declared thiqah (trustworthy), and he is layyin (somewhat weak).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الفتن - أعاذنا الله منها / 12269