Sahih Muslim Book - 29, Hadith - 4450

حَدَّثَنَا مُحَمَّدُ بْنُ أَبِى بَكْرٍ الْمُقَدَّمِىُّ حَدَّثَنَا سُلَيْمَانُ أَبُو دَاوُدَ حَدَّثَنَا زَائِدَةُ عَنِ السُّدِّىِّ عَنْ سَعْدِ بْنِ عُبَيْدَةَ عَنْ أَبِى عَبْدِ الرَّحْمَنِ قَالَ خَطَبَ عَلِىٌّ فَقَالَ يَا أَيُّهَا النَّاسُ أَقِيمُوا عَلَى أَرِقَّائِكُمُ الْحَدَّ مَنْ أَحْصَنَ مِنْهُمْ وَمَنْ لَمْ يُحْصِنْ فَإِنَّ أَمَةً لِرَسُولِ اللَّهِ -صلى الله عليه وسلم- زَنَتْ فَأَمَرَنِى أَنْ أَجْلِدَهَا فَإِذَا هِىَ حَدِيثُ عَهْدٍ بِنِفَاسٍ فَخَشِيتُ إِنْ أَنَا جَلَدْتُهَا أَنْ أَقْتُلَهَا فَذَكَرْتُ ذَلِكَ لِلنَّبِىِّ -صلى الله عليه وسلم- فَقَالَ « أَحْسَنْتَ ».

It was narrated that Abu 'Abdur-Rahman said: " 'Ali (may Allah honor his face) gave a speech and said: 'O people, carry out the Hadd punishments on your slaves, those who are married and those who are not married. A slave woman of the Messenger of Allah (s.a.w) committed Zina, and he told me to whip her, but she had recently given birth, and I was afraid that if I whipped her, I would kill her. I mentioned that to the Prophet (s.a.w) and he said: You have done well."'