When an act is prohibited, first ask whether the wrongness belongs to the act itself or arises from an associated feature. A separate question then concerns what legal effects, if any, follow after the prohibited act occurs.
Wrongfulness and the nullity of every resulting legal effect are not invariably interchangeable. This distinction informs the textbook's treatment of qabih li-aynihi and qabih li-ghayrihi. Particular rulings require the full conditions and evidentiary framework of the relevant school.