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."  

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  

Messenger of Allah ﷺ was asked about the slave-girl, if she was a virgin and committed illegal sexual intercourse. The Prophet ﷺ said, "If she committed illegal sexual intercourse, lash her, and if she did it a second time, then lash her again, and if she repeated the third time, then sell her even for a hair rope." Ibn Shihab said, "I don't know whether to sell her after the third or fourth offense."  

أَنَّ رَسُولَ اللَّهِ ﷺ سُئِلَ عَنِ الأَمَةِ إِذَا زَنَتْ وَلَمْ تُحْصِنْ قَالَ إِنْ زَنَتْ فَاجْلِدُوهَا ثُمَّ إِنْ زَنَتْ فَاجْلِدُوهَا ثُمَّ إِنْ زَنَتْ فَبِيعُوهَا وَلَوْ بِضَفِيرٍ قَالَ ابْنُ شِهَابٍ لاَ أَدْرِي بَعْدَ الثَّالِثَةِ أَوِ الرَّابِعَةِ