Lev 18:18 | MHM | STEP | v. 18 : A man is not allowed to marry his wife’s sister while his wife is still alive ( v. 18 ). This law was given because marrying sisters could cause jealousy and family problems, as seen in the story of Jacob. Even if polygamy was allowed at that time, taking two sisters as wives was not permitted.

‏ Leviticus 18:18

v. 18: A man is not allowed to marry his wife’s sister while his wife is still alive (v. 18 ^a). This law was given because marrying sisters could cause jealousy and family problems, as seen in the story of Jacob. Even if polygamy was allowed at that time, taking two sisters as wives was not permitted.