وَعَنْ عَلِيٍّ رضى الله عنه
قَالَ: قَالَ رَسُولُ اَللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ -«أَقِيمُوا اَلْحُدُودَ عَلَى مَا مَلَكَتْ أَيْمَانُكُمْ»
“Inflict the prescribed punishment to those whom you possess (i.e. your slaves).” Related by Abu Dawud. And it is related by Muslim (but only traced to the Companion).