Marrying a woman and her aunt at the same time
The prophet ﷺ forbade the marriage to a woman and her paternal aunt or maternal aunt at the same time. Below is a compilation from the scholars who forbid the joining between the two:
Ibn Qudama says in Al mughni:
It is not permissible for someone to marry a woman and her aunt at the same time. Ibn Al mundhir said: The scholars of the world have come together to forbid this- with the grace of Allah- there is no dispute in opinion in this matter. Apart from the people of innovation, they are from the unaccepted opinion and outsiders, for they have not forbidden this, and they have not referred to the authentic sunnah of the prophet ﷺ in which Abu Hurayra narrates: the prophet ﷺ said: (A man may not marry a woman and her paternal aunt, or a woman and her maternal aunt) Agreed upon.
In a narration of Abu Dawoud: A woman should not be married to one who had married her paternal aunt or a paternal aunt to one who had married her brother’s daughter or a woman to one who had married her maternal aunt or maternal aunt to one who had married her sister’s daughter. A woman who is elder (in relation) must not be married to one who had married a woman who is younger (in relation) to her nor a woman who is younger (in relation) must be married to one who has married a woman who is elder (in relation) to her
The reasoning behind the prohibition between the marriage of two sister to the same person is to prevent enmity between the relatives, leading to breaking the ties between the family, and this is prevalent in what we have mentioned previously.. If they protest then Allah SWA says: And lawful to you are [all others] beyond these) according to what we have narrated.
Two men from the Khawarij came to Umar bin Abdul Aziz, and some of the things they disagreed upon were stoning of adulterers and the prohibition of marriage to a woman and her aunt at the same time, and they said: “This is not in the book of Allah SWA” so Umar bin Abdul Aziz asked: “How many prayers did Allah prescribe to you” they said: “ Five prayers in the day and night” and he asked them about the number of raka’ahs (units) for each prayer and they told him, and he asked them about the amount of zakat, and they told him, so he said: “So where do you find all of these things in the book of Allah SWA” they said: “ We don’t find them in the book of Allah SWA” so he asked them: “Then how did you reach these conclusions?” They said “The prophet ﷺ did it, and the Muslims after him,” and he said: “ Well then these two are like that as well.”
There is no difference between a maternal or paternal aunt, factually or metaphorically, they are like the aunts of their father, or the aunts of their mothers, even if they are far in level, be it from the lineage or from breastfeeding. Also whenever we see two persons where one of them is not permitted to marry another, if one of them is a male and the other is a female, for the sake of lineage, then it is not permissible to join the two. This is condemned because it leads to the breaking of ties between the family, because of the competition and jealousy between the two.
Furthermore, it is not permissible to combine a woman and her daughter in the contract, for the reasons mentioned above, and because a mother and her daughter are closer to each other than two sisters, so if it is forbidden to join between two sisters then forbidding the joining between a mother and her daughter deserve this more.