as He, exalted is He, says: “And your stepdaughters—under your guardianship—born of your wives with whom you have consummated marriage.” [al-Nisa’ 4:23]

Thus, if he says to his wife, “You are to me like your daughter from so-and-so,” he has pronounced ẓihār, because he has likened her to one who is permanently forbidden to him through marital affinity. If he says, “You are to me like the back of your daughter by me,” he has pronounced ẓihār, because he has likened her to one who is permanently forbidden to him through lineage.

His words, “my mother-in-law”: a mother-in-law is one’s wife’s mother or her female relatives; but what is meant here is her mother, because the other female relatives are forbidden to him only temporarily. Thus, if he says, “You are to me like the back of your mother,” or her belly, hand, foot, nose, lip, or the like, he has pronounced ẓihār.

His words, “Or: ‘You are forbidden to me.’” If he says, “You are forbidden to me,” he has pronounced ẓihār. We have previously discussed this issue in detail. According to the madhhab, it constitutes ẓihār in every case, even if he intended divorce or an oath.

The correct view, however, is that the matter requires distinction:

First: if he says, “You are forbidden to me,” then the basic ruling is that it is an oath. Since its basic ruling is that of an oath, it takes the ruling of an oath: he must offer the expiation for an oath, after which she becomes lawful to him. The evidence for this is Allah’s saying: “O Prophet, why do you prohibit what Allah has made lawful for you, seeking to please your wives? And Allah is All-Forgiving, Most Merciful. Allah has already prescribed for you the absolution of your oaths.” [al-Tahrim 66:1–2] A wife is among that which Allah has made lawful for him; therefore, if he declares her forbidden to himself, it is an oath. The view adopted by the author and other jurists is undoubtedly weak. This is why it is authentically reported from Ibn Abbas that whoever declares his wife forbidden to himself has made an oath for which he must offer expiation. (1)