Unlawful to wed blood and foster relations -Not to marry two sisters at a time -To marry free women - Laws regards wedding slave girls.
حُرِّمَتْ عَلَيْكُمْ أُمَّهَاتُكُمْ وَبَنَاتُكُمْ وَأَخَوَاتُكُمْ وَعَمَّاتُكُمْ وَخَالاَتُكُمْ وَبَنَاتُ الأَخِ وَبَنَاتُ الأُخْتِ وَأُمَّهَاتُكُمُ اللاَّتِي أَرْضَعْنَكُمْ وَأَخَوَاتُكُم مِّنَ الرَّضَاعَةِ وَأُمَّهَاتُ نِسَآئِكُمْ وَرَبَائِبُكُمُ اللاَّتِي فِي حُجُورِكُم مِّن نِّسَآئِكُمُ اللاَّتِي دَخَلْتُم بِهِنَّ فَإِن لَّمْ تَكُونُواْ دَخَلْتُم بِهِنَّ فَلاَ جُنَاحَ عَلَيْكُمْ وَحَلاَئِلُ أَبْنَائِكُمُ الَّذِينَ مِنْ أَصْلاَبِكُمْ وَأَن تَجْمَعُواْ بَيْنَ الأُخْتَيْنِ إَلاَّ مَا قَدْ سَلَفَ إِنَّ اللّهَ كَانَ غَفُورًا رَّحِيمًا
23. " Forbidden to you (in marriage) are your mothers, and your daughters, and your sisters, and your parental aunts and your maternal aunts, and daughters of your brother and daughters of your sister, and your mothers that have suckled you, and your foster sisters, and the mothers of your wives, and your step-daughters who are in your guardianship (born) of your wives to whom you have gone in, but if you have not gone in to them, there shall not be a sin on you (to marry their daughters), and the wives of your sons who are of your own loins. And (it is forbidden to you) that you should have two sisters together (at the same time), except what has already passed, verily Allah is Forgiving, Merciful."
In this verse, those women with whom marriage is forbidden are pointed out. This prohibition comes forth through three ways:
1) Birth of progeny, genealogical relationship;
2) marriage, (casual relationship);
3) suckling, (foster relationship).
The marriages with the above mentioned relatives, which had occurred before the revelation of this verse, were forgiven. The prohibition of marriage with some relatives had been enjoined in the former divine religions, too. For example, the Torah, book of Leviticus, Chapter 18, verses 6 to 23 are as follows:
6. None of you shall approach to any that is near of kin to him, to uncover their nakedness: I am the LORD.
7. The nakedness of thy mother, shalt thou not uncover: She is thy mother; thou shalt not uncover her nakedness.
8. The nakedness of thy father's wife shalt thou not uncover: it is thy father's nakedness.
9. The nakedness of thy sister, the daughter of thy father, or daughter of thy mother, whether she be born at home, or born abroad, even their nakedness thou shalt not uncover.
10. The nakedness of thy son's daughter, or of thy daughter's daughter, even their nakedness thou shalt not uncover: for their's is thine own nakedness.
11. The nakedness of thy father's wife's daughter, begotten of thy father, she is thy sister; thou shalt not uncover her nakedness.
12. Thou shalt not uncover the nakedness of thy father's sister: she is thy father's near kinswoman.
13. Thou shalt not uncover the nakedness of thy mother's sister: for she is thy mother's near kinswoman.
14. Thou shalt not uncover the nakedness of thy father's brother; thou shalt not approach to his wife: she is thine aunt.
15. Thou shalt not uncover the nakedness of thy daughter in law: she is thy son's wife; thou shalt not uncover her nakedness.
16. Thou shalt not uncover the nakedness of thy brother's wife: it is thy brother's nakedness.
17. Thou shalt not uncover the nakedness of a woman and her daughter; neither shalt thou take her son's daughter, or her daughter's daughter, to uncover her nakedness; for they are her near kinswomen: it is wickedness.
18. Neither shalt thou take a wife to her sister, to vex her, to uncover her nakedness, beside the other in her life time.
19. Also thou shalt not approach uncover to a woman to uncover her nakedness, as long as she is put apart for her uncleanness.
20. Moreover thou shalt not lie carnally with thy neighbour's wife, to defile thyself with her.
21. And thou shalt not let any of thy seed pass through the fire to Molech; neither shalt thou profane the name of thy God: I am the LORD.
22. Thou shalt not lie with mankind, as with womankind: it is abomination.
23. Neither shalt thou lie with any beast to defile thyself therewith: neither shall any woman stand before a beast to lie down thereto: it is confusion.
1. The authority of enjoining things to be unlawful (such as alcoholic liquor, some bargains, and married women) is wholly up to Allah.
2. Consider the daughters of your wife from her previous husband who are brought into your house, as your own daughters, and be as a trainee for them, since you are their father.
3. The wives of your sons, who are from your own dynasty, are unlawful for you to marry, and the wives of your adopted sons, as well.
4. The contemporary marriage with two sisters usually draws them toward personal jealousy and competition and, finally, their love and affections may be led to detestation.
The prohibition may be for this reason. The verse says: