"My perfect one" (tammati) — "my twin" (tomati), namely she who bore me {two} twins. "My perfect one" (tammati), because it was not from Rebekah, but rather the Holy One, blessed be He, placed it in her heart. She said to him: When the first Adam sinned, was he cursed? Was it not his mother who was cursed? And now it is my turn; do what is yours, and if you should be cursed, your curse shall come upon me, as it is said (Genesis 27:13): "Upon me your curse, my son," etc. [Why?] The Holy One, blessed be He, said to him: Behold, I have crowned the blessings for you, as "my head is filled with dew" (Song of Songs 5:2). Immediately he went, as it is said (Genesis 27:14): "And he went and took and brought them to his mother," etc. He entered before his father and took the blessings, as it is said (Genesis 27:28): "And may God give you," etc.
Rebekah Takes Jacob's Curse Upon Herself for the Blessings
Midrash Tanchuma Buber, Toldot 18:4
תמתי, תומתי אותה שילדה לי (שני) תאומים, תמתי שלא היה מן רבקה, אלא הקב"ה נתן בלבה אמרה לו וכי אדם הראשון כשחטא הוא נתקלל לא אמו נתקללה ועכשיו אני, את שלך עשה, ואם תקולל עלי קללתך תבוא, שנאמר עלי קללתך בני וגו'. [למה] א"ל הקב"ה הרי עיטרתי לך את הברכות, שראשי נמלא טל, מיד הלך, וילך ויקח ויבא לאמו וגו', נכנס אצל אביו ונטל את הברכות שנאמר ויתן לך האלהים וגו'.