An-Nisa 4:25

وَمَن لَّمۡ يَسۡتَطِعۡ مِنكُمۡ طَوۡلًا أَن يَنكِحَ ٱلۡمُحۡصَنَٰتِ ٱلۡمُؤۡمِنَٰتِ فَمِن مَّا مَلَكَتۡ أَيۡمَٰنُكُم مِّن فَتَيَٰتِكُمُ ٱلۡمُؤۡمِنَٰتِۚ وَٱللَّهُ أَعۡلَمُ بِإِيمَٰنِكُمۚ بَعۡضُكُم مِّنۢ بَعۡضٖۚ فَٱنكِحُوهُنَّ بِإِذۡنِ أَهۡلِهِنَّ وَءَاتُوهُنَّ أُجُورَهُنَّ بِٱلۡمَعۡرُوفِ مُحۡصَنَٰتٍ غَيۡرَ مُسَٰفِحَٰتٖ وَلَا مُتَّخِذَٰتِ أَخۡدَانٖۚ فَإِذَآ أُحۡصِنَّ فَإِنۡ أَتَيۡنَ بِفَٰحِشَةٖ فَعَلَيۡهِنَّ نِصۡفُ مَا عَلَى ٱلۡمُحۡصَنَٰتِ مِنَ ٱلۡعَذَابِۚ ذَٰلِكَ لِمَنۡ خَشِيَ ٱلۡعَنَتَ مِنكُمۡۚ وَأَن تَصۡبِرُواْ خَيۡرٞ لَّكُمۡۗ وَٱللَّهُ غَفُورٞ رَّحِيمٞ 25

And whoever among you cannot [find] the means to marry free, believing women, then [he may marry] from those whom your right hands possess of believing slave girls. And Allah is most knowing about your faith. You [believers] are of one another. So marry them with the permission of their people and give them their due compensation according to what is acceptable. [They should be] chaste, neither [of] those who commit unlawful intercourse randomly nor those who take [secret] lovers. But once they are sheltered in marriage, if they should commit adultery, then for them is half the punishment for free [unmarried] women. This [allowance] is for him among you who fears sin, but to be patient is better for you. And Allah is Forgiving and Merciful