Nikah with the Wife’s Sister

Question

Zayd married Hinda, but a few days later he married Hinda’s own full sister, while Hinda was already in his nikah. What we wish to know is: is the second nikah valid or not? If it is not valid, will it have any effect on the first wife or not?

Answer

Keeping two sisters in nikah at the same time is haram, by the words of the Exalted: [ar]وَأَن تَجْمَعُوا۟ بَيْنَ ٱلْأُخْتَيْنِ[/ar] “…and that you combine two sisters…” (Surah al-Nisa’, 4:23). In the case asked about, the second nikah is batil (void). [ar]ولو تزوج أختين في عقدين ولم تعلم الأولى…

Source: Fatawa Mahmudiyya

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