the father, and from the mother, whether the grandfather was near or distant, an heir or not, due to His saying, the Exalted: "...and your paternal aunts." As for maternal aunts, they are the sisters of the mother from the three aspects, and the sisters of the grandmothers, however high they ascend. We have already mentioned that every grandmother is a mother, so likewise, every sister of a grandmother is a forbidden maternal aunt, due to His saying, the Exalted: "...and your maternal aunts." [The daughters of a brother, every woman who is linked to a brother by birth, is a forbidden daughter of a brother, from whichever side the brother is, due to His saying, the Exalted: "...and the daughters of the brother." (7)] The daughters of a sister are likewise forbidden, due to His saying, the Glorified and Exalted: "...and the daughters of the sister." These, then, are the women prohibited by lineage.

The second type: those prohibited by reason [of a cause], and they are of two categories: breastfeeding and affinity. As for breastfeeding, those explicitly mentioned in the text regarding their prohibition are two: nursing mothers, and they are those who breastfed you, their mothers, and their grandmothers, no matter how high their degree ascends, according to what we mentioned regarding lineage; they are forbidden by His saying, the Exalted: "...and your mothers who suckled you and your sisters through suckling." Every woman who suckled you, or whose mother suckled you, or whom your mother suckled, or whom one woman suckled along with you, or if you and she were nursed from the milk of one man—as in the case of a man who has two wives, both of whom have milk from him, and one of them suckled you and the other suckled her—then she is your sister and is forbidden to you, due to His saying, the Glorified: "...and your sisters through suckling."

The second category: prohibition by affinity, and those explicitly mentioned are four: mothers of one's wives. Whoever marries a woman, every mother of hers—by lineage or by breastfeeding, near or distant—becomes forbidden to him simply by the contract. Ahmad explicitly stated this, and it is the opinion of the majority of scholars, including Ibn Mas'ud, Ibn Umar, Jabir, Imran ibn Husayn, and many of the Tabi'in. Malik, al-Shafi'i, and the scholars of opinion (Ahl al-Ra'y) also hold this view. It was narrated from Ali, may Allah be pleased with him, that she does not become forbidden except by consummating the marriage [with her daughter, just as her daughter does not become forbidden except by consummation] (8). Our argument is the saying of Allah the Exalted: "...and the mothers of your wives." She is a woman to whom one has tied the marriage contract, so her mother enters into the generality of the verse. Ibn Abbas said: "Leave ambiguous what the Qur'an has left ambiguous" (9), meaning...