'Ali (RAA) narrated that the Messenger of Allah (ﷺ) said:
"Inflict the prescribed punishment to those whom you possess (i.e. your slaves)." Related by Abu Dawud and Muslim (but only traced to the Companion). (ID)
English reference (ID): Book 10, Hadith 1250 (ID)
Arabic reference (ID): Book 10, Hadith 1211 (ID)