If one of you cannot afford to marry a believing gentlewoman (let him marry) a maid who is a believer. God is aware of your faith: The one of you is of the other; so marry them with the consent of their people, and give them an appropriate dowry. They are women (seeking) wedlock, and not lechery, nor secretly looking for paramours. But if they are married and guilty of adultery, inflict on them half the punishment (enjoined) for gentlewomen. This is for those who are afraid of doing wrong. In case they can wait, it is better for them. God is forgiving and kind.
— Quran 4:25