But if you intend to replace a wife by another and you have given one of them a Qintar (of gold i.e. a great amount as Mahr), take not the least bit of it back; would you take it wrongfully without a right and (with) a manifest sin? (20) And how could you take it (back) while you have gone in unto each other, and they have taken from you a firm and strong covenant? (21) And marry not women whom your fathers married, except what has already passed; indeed it was shameful and most hateful, and an evil way. (22) Forbidden to you (for marriage) are: your mothers, your daughters, your sisters, your father's sisters, your mother's sisters, your brother's daughters, your sister's daughters, your foster mother who gave you suck, your foster milk suckling sisters, your wives' mothers, your step daughters under your guardianship, born of your wives to whom you have gone in - but there is no sin on you if you have not gone in them (to marry their daughters), - the wives of your sons who (spring) from your own loins, and two sisters in wedlock at the same time, except for what has already passed; verily, Allâh is Oft¬Forgiving, Most Merciful. (23)