"Forbidden to you (in marriage) are your mothers...

"Forbidden to you (in marriage) are your mothers, and your daughters, and your sisters, and your parental aunts and your maternal aunts, and daughters of your brother and daughters of your sister, and your mothers that have suckled you, and your foster sisters, and the mothers of your wives..." Consider the daughters of your wife from her previous husband who are brought into your house, as your own daughters, and be as a trainee for them, since you are their father. "...

and your step-daughters who are in your guardianship (born) of your wives to whom you have gone in, but if you have not gone in to them, then there shall not be a sin on you (to marry their daughters)..." The wives of your sons, who are from your own dynasty, are unlawful for you to marry, and the wives of your adopted sons, as well. "...

and the wives of your sons who are of your own loins" The contemporary marriage with two sisters usually draws them toward personal jealousy and competition and, finally, their love and affections may be led to detestation. The prohibition may be for this reason. The verse says: "... And (it is forbidden to you) that you should have two sisters together (at the same time)..."…