Are the married fornicator and the unmarried fornicator—who differ in their prescribed punishments, such as stoning and lashing—equal in responsibility before God for this fornication, or do they differ?

Adultery is a grave indecency and one of the major sins. The sinfulness of this indecency increases depending on the perpetrator and the victim. It is a greater sin for a married person, as evidenced by the difference in their prescribed punishments, and because marriage prevents a person from committing such indecency. It is also a greater sin with the wife of one's neighbor, as indicated by the Prophet's (peace and blessings be upon him) saying: "That you commit adultery with your neighbor's wife." Sins become graver depending on who committed them, against whom they were committed, and in what time or place they occurred; thus, they are graver in sacred times and places.