Musnad Ahmad 27:1211

Abu al-Nadr narrated to us, Sharik narrated to us, from Mu'awiyah ibn Ishaq, from Abu Salih al-Hanafi, from a man among the companions of the Prophet, may Allah bless him and grant him peace—I think it is Ibn Umar—who said: I heard the Messenger of Allah, may Allah bless him and grant him peace, say: "Whoever mutilates a living being, then does not repent, Allah will mutilate him on the Day of Resurrection."