Sunan Abi Dawud
Hadith #5159
Abu Mas’ud al-Ansari said:when I was beating a servant of mine, I heard a voice behind me saying: know, Abu Mas’ud-Ibn al-Muthanna said: “twice”-that Allah has more power over you than you have over him. I turned round and saw that it was that it was the prophet (May peace be upon him). I said : Messenger of Allah! He is free for Allah’s sake. He said : If you had not done it, fire would have burned you or the fire would have touched you