ما هو حكم الإسلام في رجل تزوج من أخوات؟

It is forbidden to combine two sisters in marriage, whether by blood or by suckling, due to the Almighty's saying: {And that you take [in marriage] two sisters simultaneously, except for what has already occurred. Indeed, Allah is Forgiving and Merciful.}

If they are combined in one contract, both contracts are annulled. However, if he marries one of them and then the other, the second contract is invalidated, and the first contract remains valid.

It is permissible to marry the sister of the wife after the divorce of the first wife and the completion of her iddah (waiting period).