Sahih Muslim Book 17, Hadith Number 4221.

Chapter : Stoning to death of jews and other Dhimmis in case of adultery.

Abu Huraira reported that Allah’s Messenger (may peace be upon him) was asked about the slave-woman who committed adultery and was not protected (married). He said: If she commits adultery, then flog her and it she commits adultery again, then flog her and then sell her even for a rope. Ibn Shihab said: I do not know whether he said this (his statement pertaining to the sale of slave-woman) at the third or the fourth time. Ibn Shihab said that the word) dafir (used in the text) means rope.