حَدَّثَنِي مَالِكٌ، عَنِ ابْنِ شِهَابٍ، عَنْ عُبَيْدِ اللَّهِ بْنِ عَبْدِ اللَّهِ بْنِ عُتْبَةَ بْنِ مَسْعُودٍ، عَنْ أَبِي هُرَيْرَةَ، وَزَيْدِ بْنِ خَالِدٍ الْجُهَنِيِّ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم سُئِلَ عَنِ الأَمَةِ إِذَا زَنَتْ وَلَمْ تُحْصِنْ فَقَالَ ‏"‏ إِنْ زَنَتْ فَاجْلِدُوهَا ثُمَّ إِنْ زَنَتْ فَاجْلِدُوهَا ثُمَّ إِنْ زَنَتْ فَاجْلِدُوهَا ثُمَّ بِيعُوهَا وَلَوْ بِضَفِيرٍ ‏"‏ ‏.‏ قَالَ ابْنُ شِهَابٍ لاَ أَدْرِي أَبَعْدَ الثَّالِثَةِ أَوِ الرَّابِعَةِ ‏.‏

Malik related to me from Ibn Shihab from Ubaydullah ibn Abdullahibn Utba ibn Masud from Abu Hurayra and Zayd ibn Khalid al-Juhani thatthe Messenger of Allah, may Allah bless him and grant him peace, wasasked about a slave-girl who committed fornication and was notmuhsana. He said, "If she commits fornication, then flog her. If shecommits fornication again, then flog her, and if she commitsfornication again, then sell her, if only for a rope." IbnShihab added, "I don't know whether it was three or four times." Translation Not Available

Book Ref: Muwatta Imam Malik Book 41 Hadith 1516
Web Ref:  Muwatta Imam Malik Book 41 Hadith 14