سورة An-Noor ( The Light ) - الآية 33

Let those who cannot afford marriage keep themselves chaste until Allah suffices them from His bounty. If any of your slaves wishes to enter the contract of emancipation[24], make this contract with them, if you find goodness in them, and give them some of the wealth that Allah has given you. Do not compel your slave girls into prostitution – if they wish to keep chaste – seeking the worldly gains of this life[25]. But if anyone compels them, then Allah, after such a compulsion, is All-Forgiving, Most Merciful.