Musnad Ahmad 5:577

Abdullah narrated to us, Muhammad ibn Bakkar, the freed slave of Banu Hashim, and Abu al-Rabi’ al-Zahrani narrated to me, they said: Abu Waki’ al-Jarrah ibn Mulayh narrated to us, from ‘Abd al-A’la al-Tha’labi, from Abu Jamilah, from ‘Ali. And Abu al-Rabi’ said in his narration: From Maysarah Abu Jamilah, from ‘Ali, that he said: The Messenger of Allah (peace and blessings of Allah be upon him) sent me to a black slave woman of his who had committed adultery, in order to administer the prescribed punishment (hadd) to her. He said: So I found her in her blood (i.e., postpartum bleeding). I came to the Prophet (peace and blessings of Allah be upon him) and informed him of that. He said to me: "When she has recovered from her postpartum bleeding, flog her fifty [times]." And Abu al-Rabi’ said in his narration: He said: So I informed the Prophet (peace and blessings of Allah be upon him), and he said: "When she has dried from her blood, then administer the hadd to her." Then he said: "Establish the prescribed punishments."