Article 89 of Jaafari Personal Status Law

The marriage contract, absolutely, whether or not the husband has consummated the marriage, permanently prohibits three categories: 1 - The father's wife, however far ascended, such as a grandfather, whether paternal or maternal, is prohibited to the son, however far descended, whether the descendant is a son's son or a daughter's son. 2 - The son's wife is prohibited to the father, however far ascended. 3 - The wife's mother, however far ascended, absolutely, whether by consanguinity or breastfeeding.