All perfect praise be to Allah the Lord of the Worlds. May His peace and blessings be upon Prophet Mohammad and upon all his family and companions.
Al-Zihar is an Islamic term referring to a husband's declaration that his wife is forbidden to him, comparing her to a Mahram (a woman who is permanently forbidden to marry), such as his mother or sister.
The words of Zihar can either be explicit, requiring no intention for it to occur, or they can be figurative, requiring intention for it to be valid. Sheikh Al-Islam Zakariya Al-Ansari (may Allah have mercy on him) stated: "The second element is the formula for Zihar, and its explicit form is: 'You are to me like the back of my mother,' and similarly, 'You are like the back of my mother' with the omission of the connection, just as the statement 'You are divorced' is explicit, even if the words 'from me' are not said, because that meaning is immediately understood. The connection words like 'from me,' 'with me,' and 'at my place' also apply to parts of the body like the back, hands, feet, hair, chest, abdomen, private parts, and other body parts such as the soul, self, and body. Words like 'You are like my mother's hands,' 'her feet,' 'her hair,' or 'her body' fall under this rule. This is because the wife is being compared to part of the mother’s body, or to something encompassing the back, making it akin to being compared to the back itself. This is because all of these parts are prohibited for intimacy, just like the back. However, words referring to honor or sanctity, even though they are not body parts like 'my mother' and 'her eyes,' or 'her head' and 'her soul,' are not explicit but figurative in Zihar and divorce, and they only apply with intention." [Asna Al-Matalib/Vol. 3/P.358].
If a husband says to his wife, "You are forbidden to me as my sister is," this phrase is not explicit in Zihar (the analogy to the back of the mother). It is ambiguous and can refer to Zihar or something else, depending on the husband's intention. If he intends it as Zihar, the ruling is that it constitutes Zihar, and he must fast for two consecutive months before having intercourse with her. If he is unable to do so, he must feed sixty needy people. If he intends it as divorce, then the ruling is that it is a divorce. If he intends it as a prohibition on intimate relations with her, then he must pay the expiation for an oath.
In conclusion, if a man says to his wife: "You are forbidden to me as my sister is," this is considered a figurative expression, and its ruling depends on the husband's intention. If he intends Zihar, it is considered Zihar. If he intends divorce, it is considered a divorce. If he does not intend anything specific, he must pay the expiation for an oath, similar to the expiation for breaking an oath. And Allah The Almighty Knows Best.
