(22) But the children struggled in her womb, and she said, “If so, why do I exist?” She went to inquire of Adonai,
(כב) ויתרוצצו עַ"כָּ הַמִּקְרָא הַזֶּה אוֹמֵר דָּרְשֵׁנִי, שֶׁסָּתַם מַה הִיא רְצִיצָה זוֹ וְכָתַב אִם כֵּן לָמָּה זֶה אָנֹכִי? רַבּוֹתֵינוּ דְרָשׁוּהוּ לְשׁוֹן רִיצָה; כְּשֶׁהָיְתָה עוֹבֶרֶת עַל פִּתְחֵי תוֹרָה שֶׁל שֶׁם וְעֵבֶר, יַעֲקֹב רָץ וּמְפַרְכֵּס לָצֵאת, עוֹבֶרֶת עַל פֶּתַח עֲבוֹדַת אֱלִילִים, עֵשָׂו מְפַרְכֵּס לָצֵאת דָּבָר אַחֵר מִתְרוֹצְצִים זֶה עִם זֶה וּמְרִיבִים בְּנַחֲלַת שְׁנֵי עוֹלָמוֹת
(22) ויתרצצו AND [THE CHILDREN] STRUGGLED — You must admit that this verse calls for a Midrashic interpretation since it leaves unexplained what this struggling was about and it states that she exclaimed “If it be so, wherefore did I desire this” (i.e. she asked whether this was the normal course of child-bearing, feeling that something extraordinary was happening). Our Rabbis explain that the word ויתרוצצו has the meaning of running, moving quickly: whenever she passed by the doors of the Torah (i. e. the Schools of Shem and Eber) Jacob moved convulsively in his efforts to come to birth, but whenever she passed by the gate of a pagan temple Esau moved convulsively in his efforts to come to birth (Genesis Rabbah 63:6). Another explanation is: they struggled with one another and quarrelled as to how they should divide the two worlds as their inheritance (Yalkut Shimoni on Torah 111:2).
Sefer Hasidim
Lest Jacob learn from Esau, God placed enmity in their hearts even before they were born, and the divide between them started at that time.
(23) and Adonai answered her, “Two nations are in your womb, Two separate peoples shall issue from your body; One people shall be mightier than the other, And the older shall serve the younger.”
(כה) וַיֵּצֵ֤א הָרִאשׁוֹן֙ אַדְמוֹנִ֔י כֻּלּ֖וֹ כְּאַדֶּ֣רֶת שֵׂעָ֑ר וַיִּקְרְא֥וּ שְׁמ֖וֹ עֵשָֽׂו׃(כו) וְאַֽחֲרֵי־כֵ֞ן יָצָ֣א אָחִ֗יו וְיָד֤וֹ אֹחֶ֙זֶת֙ בַּעֲקֵ֣ב עֵשָׂ֔ו וַיִּקְרָ֥א שְׁמ֖וֹ יַעֲקֹ֑ב וְיִצְחָ֛ק בֶּן־שִׁשִּׁ֥ים שָׁנָ֖ה בְּלֶ֥דֶת אֹתָֽם׃(כז) וַֽיִּגְדְּלוּ֙ הַנְּעָרִ֔ים וַיְהִ֣י עֵשָׂ֗ו אִ֛ישׁ יֹדֵ֥עַ צַ֖יִד אִ֣ישׁ שָׂדֶ֑ה וְיַעֲקֹב֙ אִ֣ישׁ תָּ֔ם יֹשֵׁ֖ב אֹהָלִֽים׃(כח) וַיֶּאֱהַ֥ב יִצְחָ֛ק אֶת־עֵשָׂ֖ו כִּי־צַ֣יִד בְּפִ֑יו וְרִבְקָ֖ה אֹהֶ֥בֶת אֶֽת־יַעֲקֹֽב׃
(25) The first one emerged red, like a hairy mantle all over; so they named him Esau. (26) Then his brother emerged, holding on to the heel of Esau; so they named him Jacob. Isaac was sixty years old when they were born.(27) When the boys grew up, Esau became a skillful hunter, a man of the outdoors; but Jacob was a mild man who stayed in camp.(28) Isaac favored Esau because he had a taste for game; but Rebekah favored Jacob.
(כח) כי ציד בפיו. היה מביא ציד בפיו
He would bring food for his father to eat.
Read Genesis 27:1-40
(יג) עלי קללתך - עלי ועל צווארי כלומר: כי הייתה בוטחת במה שאמר לה הקב"ה: ורב יעבד צעיר.
(13) עלי קללתך, upon me and my neck; she was relying on the prophecy she had received during her pregnancy that the older son would serve the younger one (25,23)
(יג) עלי קללתך בני. פי' לא יקלל אותך כי אם אותי שכן דרך העולם כשהילדים עושין שלא כדת שמקללין אביהן ואמן ואומרים ארור שזה גדל:
(13) עלי קללתך בני, “may any curse your father curses you with strike me instead.” What Rivkah meant by these words was that: “your father would not curse you, but me.” It is something generally accepted that when children do not behave in the manner they should, it is their parents that are blamed for not bringing them up properly.
(כז) וירח וגו' וַהֲלֹא אֵין רֵיחַ רַע יוֹתֵר מִשֶּׁטֶף הָעִזִּים? אֶלָּא מְלַמֵּד, שֶׁנִּכְנְסָה עִמּוֹ רֵיחַ גַּן עֵדֶן;
(27) ’וירח וגו AND HE SMELLED etc.— Surely there is no more offensive smell than that of washed goat-skins! But Scripture implicitly tells us that the perfume of the Garden of Eden entered the room with him (Genesis Rabbah 65).
(כז) והתשובה בזה, שמבואר הוא בפסוק (בראשית כה כח) כי יצחק היה אוהב את עשו, ואין ספק שלא היה מכיר את מעשיו הרעים כמו שהודיעונו רבותינו ז"ל (תנחומא תולדות על הכתוב בראשית כה כח). ואילו באתהו הנבואה שיניח בנו בכורו אשר אהב ויברך את יעקב, אין ספק שהיה מתעצב בזה, ויהיה עצבונו סיבה שלא תחול עליו רוח השם יתברך על השלמות, ולזה רצה השם יתברך שיהיה סבור לברך בנו עשו אהובו, כדי שיתרחב לבו וישמח, וישיג רוח אלקי בתכלית מה שהיה אפשר לו להשיג. והיא הסיבה במה שאמר יצחק לעשו (שם כז ד) ועשה לי מטעמים כאשר אהבתי והביאה לי ואוכלה בעבור תברכך נפשך, כדי שתתרחב נפשו ותשמח, ויחול עליו רוח נבואיי.
(27) The answer: Scripture makes it clear that Isaac loved Esau, undoubtedly not knowing of his evil deeds, as our sages have apprised us (Tanchuma, Toldoth 8). And if there had come to him a prophecy that he put aside his eldest son, whom he loved, and bless Jacob instead, there is no doubt that this would have saddened him; and this sadness would have prevented the spirit of Adonai from coming to rest upon him in perfection. For this reason the Blessed One desired him to think that he was blessing his beloved son, Esau, so that his heart expand in joy and he attain the divine spirit to the full extent of his powers. And this is, likewise, the reason for Isaac's saying to Esau (Genesis 27:4): "And make me savory food, as I love, and bring it to me and I will eat it, so that my soul bless you." That is, so that his soul expand and rejoice and the spirit of prophecy come to rest upon it. And it is because of this factor that the Blessed One desired that Jacob think he was blessing Esau when he was, in reality, blessing Jacob.
The moment Isaac heard his son mention God's name (27:20) he knew it was Jacob, and not Esau. [Midrash] - Torah: A Modern Commentary, Plaut. 189.
Rashi, basing himself on various midrashim, offers three different reasons that would account for Isaac's debility: One, verse 1 follows directly on the statement that because Esau had married a foreign woman, the father's grief cause his eyes to dim. Two, the angels cried when they saw Abraham ready to kill his son, and their tears fell into Isaac's eyes; a metaphor that depicts the permanent injury done to him. Three, Isaac wanted Jacob to have the blessing all along and thus 'turned a blind eye' to the charade.
- Torah: A Modern Commentary, Plaut. 189.
If Isaac did recognize Jacob, why then is he pictured as asking his son a series of repetitive questions about his identity? “Who are you, my son?” “Come closer that I may feel you, my son—whether you are really my son Esau or not!” “Are you really my son Esau?” These piercing questions have another purpose. When Isaac asks Jacob, “Mi ata beni” (Who are you, my son?), he is giving him the opportunity to acknowledge who he is and what he is doing, since the decision is already made as to who will receive the blessing. He is really asking, “What is your makeup?” “What is your essential nature?” “Are you Jacob or Esau, or both?”
- Rabbi Norman Cohen in Self, Struggle & Change sourced from "On Being Blind by Eric Contzius
(6) Esau sallied forth to procure what his father desired, little reckoning the whence or how, whether by robbery or theft. To hinder the quick execution of his father's order, God sent Satan on the chase with Esau. He was to delay him as long as possible. Esau would catch a deer and leave him lying bound, while he pursued other game. Immediately Satan would come and liberate the deer, and when Esau returned to the spot, his victim was not to be found. This was repeated several times. Again and again the quarry was run down, and bound, and liberated, so that Jacob was able meanwhile to carry out the plan of Rebekah whereby he would be blessed instead of Esau.
(6) In spite of his great respect for his mother, Jacob refused at first to heed her command. He feared he might commit a sin, especially as he might thus bring his father's curse down upon him. As it was, Isaac might still have a blessing for him, after giving Esau his. But Rebekah allayed his anxieties, with the words: "When Adam was cursed, the malediction fell upon his mother, the earth, and so shall I, thy mother, bear the imprecation, if thy father curses thee. Moreover, if the worst comes to the worst, I am prepared to step before thy father and tell him, 'Esau is a villain, and Jacob is a righteous man.' "