Prescribed Punishments (Kitab Al-Hudud)
Dawud :: Book 38 : Hadith 4445
Narrated Salamah ibn al-Muhabbaq:
The Apostle of Allah (peace_be_upon_him) made a decision about a man who had intercourse with his wife's slave-girl as follows. If he forced her, she is free, and he shall give her mistress a slave-girl similar to her; if she asked him to have intercourse voluntarily, she will belong to him, and he shall give her mistress a slave-girl similar to her.