Al-Quran- Sura No(24), Ayat(33)

And let those who cannot find a match keep chaste till Allah give them independence by His grace. And such of your slaves as seek a writing of emancipation, write it for them if ye are aware of aught of good in them, and bestow upon them of the wealth of Allah which He hath bestowed upon you. Force not your slave-girls to whoredom that ye may seek enjoyment of the life of the world, if they would preserve their chastity. And if one force them, then unto them, after their compulsion, lo! Allah will be Forgiving, Merciful.