Question: What is the Islamic ruling on a man who swears an oath of divorce or of ẓihār (the pre-Islamic form of separation in which a husband likens his wife to a woman permanently forbidden to him) against his wife, ordering her not to do a certain act, then departs on a journey and does not know whether she has violated his oath? If she does violate it while he remains unaware, what is the ruling?

Answer: If he uttered the formula of divorce or ẓihār only with the aim of preventing her from carrying out that act, the declaration takes the legal status of an oath. He must therefore pay the expiation for breaking an oath, and the restriction is lifted. However, if—in his absence—she went ahead and did what he had forbidden and on account of which he swore, the oath is deemed broken even though he is unaware of it, because he had sworn that she must not do it and she has contravened the oath. When she knowingly and deliberately breaks the oath, the one who pronounced it becomes sinful and must offer the expiation, whether or not he ever learns of her breach.

Question: In that case, if she is considered divorced, does her waiting period (ʿiddah) begin from the moment she violated the oath?

Answer: She is not divorced if his purpose in invoking divorce was merely to prevent her from doing the act; in that circumstance it counts as an oath that can be dissolved by offering the expiation. But if his intention was that she would in fact be divorced should she do it, then she becomes divorced from the very moment she performs that act—provided she does so knowingly and by her own choice despite the oath.

Question: What if her waiting period ends and he still has no idea that she disobeyed him?

Answer: The waiting period is not tied to his knowledge; it is tied to the occurrence of the event upon which the divorce was suspended. Once she does the deed he forbade—the deed upon which the divorce was conditioned—the divorce takes effect from that moment, and her waiting period runs its course, whether it is completed by menstrual cycles or by the passage of months, irrespective of whether he knows about it or not.

Question: So if he then has marital relations with her after that, would such relations be unlawful, and would she incur the greater sin because she caused the situation while he is ignorant of what she did?