Narrated Abu Huraira:

The Prophet ﷺ said, "If a slave-girl commits illegal sexual intercourse and it is proved beyond doubt, then her owner should lash her and should not blame her after the legal punishment. And then if she repeats the illegal sexual intercourse he should lash her again and should not blame her after the legal punishment, and if she commits it a third time, then he should sell her even for a hair rope."

حَدَّثَنَا عَبْدُ اللَّهِ بْنُ يُوسُفَ، حَدَّثَنَا اللَّيْثُ، قَالَ حَدَّثَنِي سَعِيدٌ الْمَقْبُرِيُّ، عَنْ أَبِيهِ، عَنْ أَبِي هُرَيْرَةَ ـ رضى الله عنه ـ أَنَّهُ سَمِعَهُ يَقُولُ قَالَ النَّبِيُّ ﷺ
" إِذَا زَنَتِ الأَمَةُ فَتَبَيَّنَ زِنَاهَا فَلْيَجْلِدْهَا، وَلاَ يُثَرِّبْ، ثُمَّ إِنْ زَنَتْ فَلْيَجْلِدْهَا، وَلاَ يُثَرِّبْ، ثُمَّ إِنْ زَنَتِ الثَّالِثَةَ فَلْيَبِعْهَا، وَلَوْ بِحَبْلٍ مِنْ شَعَرٍ ".