Seforno: Clearly, although Yitzchak did not see through Esav, he did not consider him automatically worthy ¹ of the Berachos. ² Consequently, he made him first work to bring him food, to fulfill the Mitzvah of Kibud Av, against which he would merit the Berachos. ³

Chizkuni, Moshav Zekenim, Sha'alos u'Teshuvos Maharam: So that Yitzchak should bless him with a full heart, because the Shechinah only rests on a Lev Shalem and where there is Simchah. ⁴

Oznayim la'Torah: Because it is essential for the Mevarech to see the person he is blessing, ⁵ and, due to his blindness, Yitzchak could not see Esav while blessing him, he made up for the deficiency by applying the other four senses; Taste - He ate from his venison; Hearing - he asked him "Mah Zeh Miharta Limtzo, Beni?," in order to hear his reply; Touch - he felt him to substantiate that his hands were hairy. Smell - he smelt the aroma of his clothes.

Malbim (to 27: 3,4): A B?rachah requires a. that the recipient prepare himself; b. the giver rise and cling to the Source of B?rachah; c. connection between the giver and the recipient. Eisav would prepare himself through Kibud Av, for which the Torah promises long life. To reach Devekus, Yitzchak would eat. This is like a bribe to the body to allow the Nefesh to leave (unlike its nature) and cling to spirituality. Making the food the way I like and giving to me is for the connection.

Ramban and Rashbam ¹ : The B?rachos of Avraham, to inherit Eretz Cana'an, and that he would be the one to enter into the covenant with Hashem - because, as far as Yitzchak was concerned, Eisav was the B?chor.

Moshav Zekenim (in 27:3): From the B?rachos that Yitzchak (knowingly) gave to Ya?akov (to be a great nation, Birchos Avraham, and Eretz Cana'an ? in 28:3 & 4, we can infer that he knew Eisav's nature. ² Consequently, it was the first B?rachos that he blessed Ya?akov exclusively that he planned to bless Eisav - dew, fertile land, grain, wine, and to rule over his brothers).

Malbim: Refer to 27:1:2:3, and to 27:1:153:2.

Ramban #1: Initially, it was not correct for her to tell Yitzchak about it - particularly as she went to ask Hashem without his permission. Now she did not tell him because she figured that, due to his love for Eisav, he would not bless Ya?akov but would leave [the B?rachos] in Hashem's hands. So she opted to tell Ya?akov to pretend to be Eisav,] so Yitzchak would bless Ya?akov with a full heart.

Ramban #2: She thought that Yitzchak was a greater prophet than the one who informed her (Shem), in which case it was not necessary to inform him.

Ramban #3: It was min ha'Shamayim that she should not tell him, so that Ya?akov should receive these B?rachos; and Eisav, those of "Al Charbecha Tichyeh" (27: 39-40).

Ha'amek Davar: Refer to 24:62:1:7*.

Malbim: She would have tried to convince him now, but she knew that Eisav went "Lehavi" (he would return promptly - Refer to 27:5:2:1), so there was no time for that.

Perhaps she did tell him! The Pasuk is ambiguous. It could mean that the younger one will serve the older one, ¹ which is how Yitzchak understood it - due to "Ki Tzayid be'Fiv" (25:28). Rivkah on the other hand, grew up among Resha'im and recognized Eisav's evil. She was sure that the older will serve the younger. (PF)

Yitzchak was a Navi, but she had to go to Shem to hear "ve'Rav Ya'avod Tza'ir" (25:23). She reasoned that if Hashem does not want to reveal it to Yitzchak, how could she reveal it?' ² (PF)

Ha'amek Davar: Make the food with intent for me, so you will have more merit. After preparing it in my house, bring it to my room.

Ha'amek Davar: It is my desire.