Ali said:You people must carry out the punishment on your slaves, those of them who are married and those who are not, for a slave woman belonging to God’s Messenger committed fornication and he ordered me to beat her. But she had recently given birth to a child and I was afraid that if I beat her I might kill her, so I mentioned that to the Prophet and he said, “You have done well." Muslim transmitted it. In a version by Abd Dawud he said, “Leave her till her blood stops flowing and then carry out the punishment on her, and carry out* the punishment on your female slaves”. Abu Dawud. *Here the verb is plural.
Hadith Referenceمشكوة المصابيح / كتاب الحدود / 3564
Hadith Gradingالألبانی:صَحِيح | زبیر علی زئی:صحيح
Hadith Takhrij´تحقيق و تخريج: محدث العصر حافظ زبير على زئي رحمه الله` «رواه مسلم (1705/34) و أبو داود (4473)»