(In the light of Surah an-Nisa Ayah 23)
وَأُمَّهَـتُ نِسَآئِكُمْ And the mothers of your wives: Also unlawful to husbands are the mothers of their wives. Here too, the “ummahat” includes all grandmothers of wives, maternal, paternal, lineal or foster.
Just as the mother of a legally wedded wife is unlawful, very similarly, equally unlawful is the mother of a woman with whom one has slept assuming her to be his wife, (while, in fact, she was not his wife) or with whom zina has been committed, or who has been touched lustfully.
The initial bond or marriage, in itself, renders the mother of one’s wife unlawful for him. it means that even if the husband has never slept with his wife, her mother is still unlawful for him to marry.
وَرَبَائِبُكُمُ اللَّـتِى فِى حُجُورِكُمْ مِّن نِّسَآئِكُمُ اللَّـتِى دَخَلْتُمْ بِهِنَّ And your step-daughters under your care who are born of your women with whom you have had intercourse: When one marries a woman and sleeps with her after the marriage, the daughter of that woman from another husband becomes unlawful for him, and so do her granddaughters, both paternal and maternal. Marriage with them is not permissible. But, if the husband has not yet slept with his wife and has divorced her after the contract of marriage, then her daughter or granddaughter will not be unlawful for him. But, following nikah, if one touches his wife lustfully, or looks at her private part with sexual desire, then this too, will be taken as having sex with her, therefore, it will make the daughter of that woman unlawful.
The words “your women” used in this context are general. Therefore, it is not the legally wedded wife only whose daughters are unlawful for the husband, but the same rule applies to a woman who is not really wedded to the person, but he has had sexual intercourse with her either under the wrong impression that she is his wife, or in adultery. The daughter and granddaughter of such women will also become unlawful for him.
وَحَلَـئِلُ أَبْنَآئِكُمُ الَّذِينَ مِنْ أَصْلَـبِكُمْ And the wives of your sons from your loins: The wife of one’s own son is unlawful, and the universality of ‘son’ includes grandsons, paternal or maternal. So, marriage with their wives shall not be permissible.
مِنْ أَصْلَـبِكُمْ From your loins: This particular restriction is used here to exclude the adopted son. Marriage with his wife is lawful. As far as a foster son is concerned, he is governed by the rule which governs the lineal son, therefore, marriage with his wife too is unlawful.
وَأَن تَجْمَعُواْ بَيْنَ الاٍّخْتَيْنِ And that you combine two sisters in wedlock: Also unlawful is the combining of two sisters in the bond of marriage. They may be real sisters or half sisters from the father’s side or sisters from the mother’s side (haqiqi, allati, akhyafi). They may be sisters by lineage or sisters by fosterage. This rule covers all of them. However, when one sister has been divorced it is permissible to marry another sister, but this permissibility becomes effective only after the period of iddah has expired. Marriage during iddah is not permissible.
Just as one cannot combine two sisters in his marriage, it is also unlawful for him to combine a paternal aunt and her niece, and a maternal aunt and her niece. They too cannot be combined in marriage with any one person. As reported in al-Bukhari and Muslim, the Prophet has said, “Do not combine a woman with her paternal aunt, nor a woman with her maternal aunt.”
Muslim jurists have mentioned the general principle that any two women, out of whom, if one was supposed to be a male, then, their marriage with each other would turn out to be incorrect according to Islamic law, thus two women of this kind cannot be combined in marriage with one man.
إَلاَّ مَا قَدْ سَلَفَ Except what has passed: It means that whatever has been the practice during jahiliyyah will not be called to account. These words have also appeared in ayah 22. There too, the meaning is the same, that is, that which came to pass during jahiliyyah has passed. Now that Islam has been embraced, past deeds will not be taken into account, but it is necessary to abstain from them in future.
In the same way, it is necessary at this time of the revelation of what was unlawful that separation be made if one holds the wife of his father or two sisters, in marriage. In the case of two sisters, it is compulsory that one sister be separated.
As narrated by the Companion Bara, Ibn Azib, the Prophet had sent Abu Burdah ibn Niyar to execute a man because he had married the wife of his father. [Mishkat, p. 274]
Ibn Firoz Dailami narrates from his father, “When I embraced Islam, I had two sisters married to me. I went to the Prophet with the problem. He said, ‘Separate by divorcing one and keeping the other’.” [Mishkat, p. 274]
These narrations tell us that just as it is not lawful, after embracing Islam; to contract marriage with father’s wife or to combine two sisters in marriage, similarly it is also unlawful to maintain such marriages, if they have been contracted by someone before he embraced Islam.
إِنَّ اللَّهَ كَانَ غَفُوراً رَّحِيما Surely, Allah is Most-Forgiving, Very Merciful: means that anything people did erroneously before the advent of Islam will be overlooked by Allah subhanahu wa ta’ala once they have embraced Islam and they can be sure that He will turn to them with the great reach of His mercy.