What is the ruling on zinā (unlawful sexual intercourse), and what about someone who has been committing it for eight years and does not know how to repent? What is the ruling on the children of zinā? Is there expiation for it, and how does one repent?

Adultery is one of the most heinous major sins and incurs Allah's wrath. Whoever falls into it must hasten to sincere repentance, which consists of abandoning the sin, regretting having committed it, and resolving never to return to it. He must conceal his sin, perform many good deeds and effacing good acts, and avoid the causes of disobedience and cut off the paths leading to it, such as lowering the gaze and avoiding seclusion with women. It is also recommended for him to hasten to marry if he is not married, to be keen on good companionship, and to make abundant supplications. As for children born out of wedlock, they are not attributed to the lineage of the fornicator.