Ja'far bin Muhammad narrated from his father that Ali (may Allah be pleased with him) said regarding Ibn Muljam when he wounded him: "Feed him, give him drink, and keep him imprisoned in a good manner. If I survive, I am the guardian of my own blood; if I wish, I will forgive him, and if I wish, I will take retribution. And if I am martyred, then kill him, but do not mutilate him."
Hadith Referenceمسند الإمام الشافعي / كتاب القتل والقصاص والديات والقسامة / 1617
Hadith Takhrijاسناده ضعيف لضعف شيخ الشافعي ولإنقطاعه بين محمد بن علی و علی بن ابی طالب: اخرجه البیهقی: 8/ 183 - وفي المعرفة السنن والآثار له (5003)۔