Ja'far bin Muhammad (may Allah have mercy on him) narrates from his father that Sayyiduna Ali (may Allah be pleased with him) used to go out at dawn with his whip, with which he would wake the people. Ibn Muljam struck him, and he said: "Feed him, give him drink and keep him well as a captive. If I live, I am myself the guardian of my blood: I will pardon him if I wish, or take retaliation from him if I wish."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنايات / 16059