SEIF 2 (Cont.)
The Dagal Mervava says that if a woman already Davened Maariv, she cannot be Moizie a male in Kiddush that didn't Daven. Since she was already Yoitze the Mitzva from the Torah she no longer has the Mitzva. So by men, even if they were already Yoitze, they may Moitzie others. This is because of the principle of Arvus (being guarantors for other people's Mitzvos.) Since he needs to make sure that the other person does his Mitzva, it's as if he's obligated, and therefore can be Moitzie that person. The Rosh says that women never accepted on themselves Arvus for other people's Mitzvos. Therefore, only while they fulfill their own obligation they can be Moitzie others. After they fulfilled their Mitzva, they're no longer obligated in that Mitzva and cannot be Moitzie others.
