Abu Hurairah (RAA) narrated that the Messenger of Allah (ﷺ) said:
"He who accuses his slave of committing adultery (without proof) will be punished with the prescribed penalty on the Day of Resurrection unless it is (true) as he said." Agreed upon. (IT)
English reference (IT): Book 10, Hadith 1266 (IT)
Arabic reference (IT): Book 10, Hadith 1227 (IT)