Nahj al-Balāgha
Hadith 1781١٨٦. وَقَالَ (عليه السلام): لِلظَّالِمِ الْبَادِي غَداً بِكَفِّهِ عَضَّةٌ.
186. Amīr al-mu’minīn, peace be upon him, said: He who takes the lead in oppression has to bite his hand (in repentance) tomorrow.