It is narrated from Sayyiduna Abu Hurairah (may Allah be pleased with him) and Sayyiduna Zayd bin Khalid al-Juhani (may Allah be pleased with him) that someone asked the Messenger of Allah (peace and blessings be upon him) about the ruling for a slave-girl who is not married (non-muhsanah) if she commits adultery. The Messenger of Allah (peace and blessings be upon him) said: "If she commits adultery, flog her. Then if she commits adultery again, flog her again. Then if she commits adultery again, flog her again." After the third or fourth time, the Messenger of Allah (peace and blessings be upon him) said: "Sell such a slave-girl, even if it is for a rope."
Imam Malik (may Allah have mercy on him) says that Ibn Shihab (may Allah have mercy on him) said: I do not know whether the command to sell her was after the third time or the fourth time.
Imam Malik (may Allah have mercy on him) said: The meaning of the word «الضَّفِيرُ» in the hadith is "rope."

It is narrated from Nafi that there was a slave appointed over those slaves and slave-girls who had come in the spoils of war. He forced himself upon one of the slave-girls among them. Sayyiduna Umar ibn al-Khattab, may Allah be pleased with him, flogged him and expelled him, and did not punish the slave-girl because she had been coerced.

It is narrated from Sayyiduna Abdullah bin Ayyash (may Allah be pleased with him) that Sayyiduna Umar (may Allah be pleased with him) ordered me and several other young men from the Quraysh to carry out the punishment of flogging. So we lashed the slave girls fifty lashes each for adultery; those slave girls belonged to the state, that is, to the Bayt al-Mal.