Nahj al-Balāgha

Hadith 3
imam-aliahl-al-baytjustice
ومن خطبة له (عليه السلام) حين بلغه خبر الناكثين ببيعته [وفيها يذم عملهم ويلزمهم دم عثمان ويتهدّدهم بالحرب]
When he received reports about those who had broken their oath of allegiance to him [and about those who accused him of ‘Uthmān’s killing]
Source: al-Sharīf al-Raḍī