The Book Pertaining to the Excellent Qualities of the Holy Prophet (may Peace be upon them) and His Companions (Kitab Al-Fada'il)
Muslim :: Book 30 : Hadith 5756
'A'isha reported that Allah's Messenger (may peace be upon him) never beat anyone with his hand, neither a woman nor a servant, but only, in the case when he had been fighting in the cause of Allah and he never took revenge for anything unless the things made inviolable by Allah were made violable; he then took revenge for Allah, the Exalted and Glorious.