Surah An-Noor 24:33

But let them who find not [the means for] marriage abstain [from sexual relations] until Allah enriches them from His bounty. And those who seek a contract [for eventual emancipation] from among whom your right hands possess - then make a contract with them if you know there is within them goodness and give them from the wealth of Allah which He has given you. And do not compel your slave girls to prostitution, if they desire chastity, to seek [thereby] the temporary interests of worldly life. And if someone should compel them, then indeed, Allah is [to them], after their compulsion, Forgiving and Merciful.