And Yitzchok davened to Hashem opposite his wife for she was barren. Hashem responded to Yitzchok's prayer and Rivka his wife became pregnant (Bereishis 25:21).
Rashi, quoting Medrash Rabbah (63:5), states that Yitzchok stood in one corner and davened (prayed) and Rivka stood in another corner and davened. Rashi also quotes the Gemara (Yevamos 64a) explaining why Hashem responded to Yitzchok's Tefillah. The Gemara there says that there is no comparison between the Tefillos (prayers) of a Tzaddik who is the child of a Tzaddik (righteous person) and the Tefillos of a Tzaddik who is the child of a Rusha (wicked person). Therefore, Hashem responded to Yitzchok and not Rivka.
It is possible that these two ideas are dependent on each other. The reason that they each had to daven in their own corners was because their Tefillos were different in their very essence. The Tefillah (prayer) of Yitzchok was the Tefillah of a Tzaddik ben Tzaddik (a Tzaddik who is the child of a Tzaddik). The Tefillah of Rivka was the Tefillah of a Tzaddik bas Rusha (a Tzaddik who is the child of a Rusha). When a Tzaddik ben Tzaddik davens for children, he davens that he should have children like his father. It is within the confines of "nature" that this should occur. A Tzaddik ben Rusha, however, davens that his children should not be like his father. This is opposite of the "natural" outcome. Since their Tefillos were inherently different they therefore davened in their own corners. This can help us understand Chazal's (our sages) statement that the Tefillos of a Tzaddik ben Tzaddik are answered first as applying to situations when the people are davening for children. In that situation their Tefillos are answered first because they are not asking for something that goes against nature.
--HaRav Shimon Schwab
...And Aisav was a man who knew the hunt, a man of the field (Bereishis 25:27).
Aisav knew how to trap the Eesh Sawdeh (Man of the Field). This Man of the Field is the Adnai HaSawdeh mentioned in the Mishnah (K'layim 8:5). It is also the Y'doenee mentioned in the Chumash. Its face, hands and legs had the appearance of a man. It was attached to the ground by means of a rope connected to its abdomen. No creature was able to come within the distance of the rope without being killed and ripped apart. If someone wanted to trap it, they had to fire numerous arrows until the rope was severed. The creature would then let out a bitter cry and die immediately. Aisav knew how to trap it alive. The explanation, then, of this posuk is: Aisav was a man who know how to trap the Eesh HaSawdeh.
--Sefer Beis Yitzchok from the Sefer Ohr Tzvi in the name of the Vilna Gaon
...And Yaakov was a wholesome man (Bereishis 25:27).
Rashi says that someone who is not sharp enough to fool others is called Tawm, wholesome. This is difficult to understand. Rashi himself (Bereishis 29:12) states on the posuk, "And Yaakov told Rochel that he was the brother of her father", if he (Lovon) comes to fool me, I am his brother in trickery.
However, Chazal say (Koheles Rabbah 7) that one who is merciful in a situation when he needs to be cruel will eventually be cruel when he needs to be merciful. A person needs to understand how to conduct himself with his character traits. Sometimes he has to act in a certain way for the sake of Heaven and sometimes in the exact opposite way for a different purpose. That is the meaning of the posuk, "Yaakov was a wholesome man". The Hebrew word for man is Eesh. Eesh can also mean controller or owner. Yaakov was the controller of his wholesomeness. His wholesomeness did not rule over him. Yaakov knew when to be Tawm.
--The Chozeh of Lublin
And Yaakov said to his father, "I am Aisav your first-born" (Bereishis 27:19).
He meant that he is to be in place of Aisav. Yaakov acquired the Birthright form Aisav and he became Aisav in this regard. From the perspective of the Birthright, Aisav was no longer called Yitzchok's firstborn.
--The Ohr HaChaim HaKodosh
