Amatul Rahmân Omer:
The fornicator and adulterer cannot have sexual relations (without lawful marriage) except with a fornicatress and adulteress or polytheistic woman (of low morality), and the fornicatress and adulteress, none can have sexual relations with her except a fornicator and adulterer or a polytheistic man (of low morality). And this (adultery and fornication) is forbidden to the believers.
