From Sahih Bukhari (Hadith 4073):
Narrated Abu Huraira:Allah's Messenger (ﷺ) (pointing to his broken canine tooth) said, "Allah's Wrath has become severe on the people who harmed His Prophet. Allah's Wrath has become severe on the man who is killed by the Apostle of Allah in Allah's Cause
Reference: Bukhari 4073