—whether the two women are sisters by blood or by foster‐nursing, whether both are free or both are bondmaids, or one is free and the other a bondmaid, whether the marriages have been consummated or not. The Almighty says: “and that you join two sisters in wedlock—except for what has already transpired” (Qur’an 4:23), meaning what occurred in the Days of Ignorance.

Al-Suyuti remarked: To the case of two sisters we must add, on the strength of the Sunnah, the prohibition of combining a woman with her paternal aunt or with her maternal aunt.

Al-Wazir said: The scholars unanimously agree that a man may not marry any woman whose simultaneous marriage with his own wife in her waiting period (‘iddah) is forbidden to him, whether that ‘iddah follows a revocable or an irrevocable divorce.

They likewise concur that the aunt of a paternal aunt takes the same ruling as the aunt herself when the first aunt is the father’s full sister, and that the aunt of a maternal aunt shares the ruling of the aunt when the first aunt is the mother’s full sister.

2 – Al-Qurtubi said: The scholars are unanimously agreed that if a man divorces his wife with a revocable divorce, he may not marry her sister until the waiting period of the divorced wife has expired. They differed, however, when the divorce is irrevocable.

• One group maintained that he may not marry the sister until the waiting period of the woman he divorced ends; this is the position of Abu Hanifah, Ahmad, and a number of the early generations.

• Another group held that he may marry the sister immediately; this is the position of al-Shafi‘i, Malik, and other predecessors.

Shaykh Taqi al-Din [Ibn Taymiyyah] stated: If the divorce is revocable, the man may not marry the other sister according to the consensus of the scholars, including the four Imams. The dispute concerns an irrevocable divorce: permissibility is the view of Malik and al-Shafi‘i, while prohibition is the view of Abu Hanifah and Ahmad.