What claim did Sarah have against Avraham?
Rashi #1: That when he prayed for children, he only prayed for himself and not for her as well. 1
Rashi #2 Targum Yonasan, Seforno and Moshav Zekenim: When Hagar disgraced her, he remained silent. 2
Because had he prayed also for her as well, perhaps she too would have been granted children!
Targum Yonasan adds that, she reminded him that she had left her land and father's household to accompany him to a foreign country and had given him her maidservant as a wife. And now that that maidservant had demeaned her, she expected him to defend her. And she concluded that, now that Avraham had remained silent, she relied on Hashem to do stand up for her, and that she would bear him children who would fill the land; consequently, there was no need for Hagar to have children.
Why does the word "u'Veinecha" have a second "Yud" (unlike other occurrences of this word)?
The Gemara says (Bava Kama 93a) that Sarah asked Hashem to judge between her and Avraham, and that therefore, she was punished first. But Hagar miscarried long before Sarah died!
Moshav Zekenim #1: Immediately, Sarah's apportioned years were reduced, before Hagar miscarried!
Moshav Zekenim #2: The miscarriage was not due to this judgment. Sarah did not care about it.
QUESTIONS ON RASHI
Rashi writes: "You should have prayed for both of us.... Furthermore, you are withholding your words [now]; you hear my disgrace and remain silent." Why does Rashi use the term "furthermore" (v'Od) rather than "alternatively" (Davar Acher)?
Gur Aryeh: The word "injustice" (Chamas) is used without specifying; it includes any injustice, and so both explanations are implied in the verse.