The Shaykh—may Allah have mercy on him—was asked:

A man is married to someone’s maternal aunt. That person has a daughter, whom the man also marries, thus being married to both his maternal aunt and his daughter. Is this marriage valid?

He replied:

It is not permissible for a man to be married simultaneously to another man’s maternal aunt and daughter, for the Prophet, may Allah bless him and grant him peace,

“forbade being married simultaneously to a woman and her paternal aunt, or to a woman and her maternal aunt.”

The four imams agree on this. They also agree that this hadith encompasses the maternal aunt of one’s father, mother, or grandmother, as well as the paternal aunt of either parent. Thus, according to the four imams, a man may not be married simultaneously to a woman and her father’s maternal aunt, or her mother’s maternal aunt.

He was also asked:

A man has married both another man’s maternal aunt and the daughter of that man’s full brother. Is it permissible for him to be married to both women simultaneously?

He replied:

Being married to both these women constitutes being married simultaneously to a woman and her father’s maternal aunt; for if her father is the other man’s brother through their mother, or through both their mother and father, then