Musannaf Ibn Abi Shaybah

Hazrat Hakam narrates that Hazrat Ali (may Allah be pleased with him) was asked about a man who divorced a woman and, during her waiting period (‘iddah), married her sister. What is the ruling regarding this? Hazrat Ali (may Allah be pleased with him) separated the two and made the dowry (mahr) obligatory upon the man. And he said that when the waiting period of the first wife is completed, he may send a marriage proposal; if he has consummated the marriage, then the full dowry will be obligatory, and the woman will have to complete the full waiting period, and both women will observe the waiting period, and the waiting period for each will be three menstrual cycles. If they do not menstruate, then they will observe the waiting period for three months.

Hazrat Amr bin Shu'aib narrates that a man divorced his wife and then married her sister. Hazrat Ibn Abbas (may Allah be pleased with them) said to Marwan: Separate the two until the waiting period ('iddah) of the divorced woman is over.

Ibrahim says that when a man marries a woman and then divorces her, and during her waiting period marries her sister, then this marriage is unlawful. Separation will be enforced between the two. The woman will not be entitled to a dowry nor will she be required to observe a waiting period.

Hazrat Zakariya narrates that Hazrat Amir was asked: If a man marries a woman, then divorces her, and during her waiting period (iddah) marries her sister, what is the ruling? He replied that separation will be enforced between the two.

Hasan considered it undesirable that a man should divorce his wife three times and then marry her sister during her waiting period.

Ibrahim says that after divorcing a woman, one cannot marry her sister during her waiting period (iddah).