Sahih Muslim
The Book of Oaths (Kitab Al-Aiman)
Book Number: 015 / Hadith Number: 4090
Abu Huraira reported that Abu'l-Qasim (one of the names of Allah's Messenger [may peace be upon him]) said: He who accused his slave of adultery, punishment would be imposed upon him on the Day of Resurrection, except in case the accusation was as he had said.