Teshuvah
Rashi (25:9) writes that Yishmael did teshuvah at the end of his life. The proof is that it states, מערת אל בניו וישמעאל יצחק אתו ויקברו המכפלה, "Yitzchak and Yishmael, his sons, buried him in the Cave of Machpeilah." Yitzchak's name is written first, which means Yishmael recognized that Yitzchak was the chosen child, so he let him go first. Rashi writes, "We learn from this that Yishmael did teshuvah, and he permitted Yitzchak to go before him. This is the (25:8) טובה שיבה, satisfying good years, that are written about Avraham's life." Avraham was niftar, seeing that his son Yishmael had done teshuvah.
The parashah begins with (23:1) שרה חיי שני, and Rashi tells us that this means שוין כולן לטובה, all of Sarah's days were good. The Daas Zekeinim m'Baalei HaTosfos (23:1) asks that also about Yishmael it states חיי שני ואלה ישמעאל. Should we say there as well that all of Yishmael's years were good years? Behold, Yishmael was a rashah for most of his life! The Daas Zekeinim replies, "Yishmael did teshuvah, as Rashi tells us... And when one converts [and does teshuvah], he becomes like a newborn. All the years before his teshuvah, all the bad that he did, aren't considered at all. He was viewed [from heaven] like someone who did teshuvah throughout his entire life."
This is the amazing power of teshuvah. It turns everything around like his entire life was good.
My grandfather, Rebbe Moshe Mordechai was conducting a tish on the second night of Rosh Hashanah. In Yerushalayim, the custom is to eat pomegranates on the second night of Rosh Hashanah, and to say Shehechiyanu on it. Before he made kiddush, his daughter, Rebbetzin Kop, knocked on the window of the mechitzah to get her father's attention and told him not to eat the pomegranate because it was wormy.
The Rebbe replied, "Then I will do teshuvah. I will become like a newborn, and I will make shehechiyanu on myself."
