Why does the Torah see fit to mention that they grew up?
Rashi: As long as they were small, it was difficult to pinpoint Esav's wickedness 1 - since 'a boy will be a boy;' and it was only when they turned Bar-Mitzvah 2 that the difference between the two brothers emerged 3 (as we shall now see).
Malbim: They grew up according to their natures. Esav did not have aptitude for intellectual pursuits, and Yaakov was simple, and did not know how to swindle.
Moshav Zekenim - Above, Rashi said (to 25:23) that from the womb, Yaakov separated to his righteousness, and Esav to his evil! Until Bar Mitzvah, the father is punished for his son's Aveiros, so people did not attribute Esav's evil to him.
Oznayim la'Torah: Interestingly, apart from selling the Bechorah and his intention to kill Yaakov, the Torah does not divulge all the terrible sins that Esav perpetrated. This is in defense of Yitzchak, who was not aware of Esav's other sins, and who could not therefore be fully taken to task for not chastising him (in the way that Avraham expelled Yishmael). See Oznayim la'Torah's comment on this with regard to raising children.
What distinction is the Torah drawing between Esav, the 'Yode'a Tzayid;' and Yaakov, the 'Ish Tam'?
Rashi: Esav would 'trap his father with his mouth,' pretending to be righteous 1 - by asking him how one gives Ma'aser from salt and straw; whereas Yaakov did put on any airs, he was an honest man who did not cheat. 2
Targum Yonasan: Esav knew how to hunt - people, and kill them. In fact, he murdered Nimrod and his son Chanoch, 3 while Yaakov, perfect in deeds, studied Torah diligently in the Yeshiva of Shem and Ever.
Rashbam: Esav was a hunter, whereas Yaakov was a shepherd for his father's flock.
Seforno: Esav was a farmer, and Yaakov lived in tents - (a) with reference to his being a shepherd, 4 and (b) where he sat and reflected about knowing his Creator.
Ramban (citing the Ibn Ezra and Radak): Esav would place (or bring) venison in the mouth of Yitzchak. 5
Ha'amek Davar: Esav trapped (swindled) people through his smooth talk, and Yaakov was pure - his heart was like his mouth.
What are the connotations of "Ish Sadeh"?
Rashi: An idle person (a Batlan), with nothing to do other than shoot animals and birds with his bow and arrow. 1
Divrei Eliyahu: This is Adnei ha'Sadeh (Kil'ayim 8:5), a creature with human semblances, but it is attached to the ground. Others could kill it; only Esav, Ish Yode'a Tzayid-Ish-Sadeh, knew how to trap it alive.
Gur Aryeh: Why does Rashi add this? The description implies some sort of action on Esav's part (and not mere inaction). Rashi explains that he would engage in idle pursuits.
In what sort of 'tents' did Yaakov dwell?
Rashi: He dwelt in the tents of (Torah) of Shem and Ever. 1
Ha'amek Davar: They were the tents of Torah and Tefilah.
Oznayim la'Torah: If Shem and Ever ran one Yeshiva, then the second Ohel refers to that of Yitzchak, since, as the Gemara states in Yoma 28b - 'Avraham, Yitzchak and Yaakov were elders who sat in Yeshiva.'
Rashi says that Esav tricked his father to think that he was pious. Even simple people recognize their children's nature. People with Ru'ach ha'Kodesh can see someone and know his deeds. How could Esav fool Yitzchak?
Lev Eliyahu (Bereishis, p. 87): As much as Yaakov was Ish Tam, Esav was Ish Tzayid - a master deceiver.
QUESTIONS ON RASHI
Rashi writes: "The youths grew up - Once they were 13 years old... [Esav] went after Avodah Zarah." But Rashi (to 25:30) writes below that Avraham died on the day that Esav left the proper path - when Esav was already 15!
Da'as Zekenim, Hadar Zekenim, Moshav Zekenim: The Yerushalmi asks this question. It answers that from age 13, he sinned covertly. After 15, he sinned openly.
Riva: A Midrash says that Yitzchak had spent two years in Gan Eden to heal from the incision made at the Akeidah. The Torah does not count those two years towards his age; as such, Yitzchak was really 62 when Esav was born, and Esav was 13 when Avraham died.
Gur Aryeh (to 25:30): Our Rashi only indicates that Esav 'went after,' i.e. he began to study the ways of Avodah Zarah at age thirteen, not that he actively worshipped it. He only began to do so at age 15.
Rashi writes: "'Skilled at trapping' (Yode'a Tzayid) - ... Esav would ask, 'Father, how does one separate Ma'aser from salt and straw?'" Why did he ask about salt and straw specifically?
Gur Aryeh: Salt and straw are completely exempt from Ma'aser, even mid'Rabanan.
Rashi writes: "He would ask, 'Father, how does one separate Ma'aser from salt and straw?'" Note that he did not ask whether one separates Ma'aser, but rather how one does so. What is meant by the question?
Gur Aryeh #1: Edible produce is obligated in Ma'aser. 1 Salt and straw are not edible produce in their own right; salt merely gives taste to other foods, and straw serves to protect the grain (called a Shomer 2 ). Esav [pretended to] imply that since we do derive benefit from them, we ought to take Ma'aser; the question was how.
Gur Aryeh #2: Neither salt nor straw are foods independently; but for opposite reasons - straw has no taste (it serves the grain), whereas salt has too much taste (it is used to flavor other foods). The Torah obligates us to give Ma'aser of produce HaSh-m has given us (Devarim 14:22) - whereas these were given to us only to enhance other items. Esav [pretended to] argue that ultimately these are from HaSh-m as well, and we ought to take Ma'aser; the question was how.
Mishnah Ma'asros 1:1.
The Shomer (protective layer) of food takes the status of food itself for certain Halachos; a) The peels of Orlah fruits are forbidden as the fruit itself (Mishnah Orlah 1:8); b) They can receive and transmit Tum'as Ochalin, and combine with the food to reach the amount of a k'Beitzah (Mishnah Uktzin 1:1). (CS)
Rashi writes: "'A man of the field' (Ish Sadeh) - an idler." Why not explain that he would work in the fields?
Gur Aryeh: If so, the verse could have used the term 'Ish ha'Adamah' (a man who works the earth - as it does regarding Noach) (9:20). "Ish Sadeh" means that Esav was always in the fields, doing nothing productive.
Rashi writes: "Tam - [Yaakov was] unversed in such deception...." Yaakov is also called Yeshurun (Devarim 32:15; from the word Yashar, upright). What is the difference between these two terms, Tam and Yashar?
Maharal (Nesivos Olam, Nesiv ha'Temimus, Ch 1, p. 205): A person who is Yashar walks the proper path - according to his own wisdom and discernment. A person who is Tam walks that path involuntarily - with Temimus (wholesomeness), without [the need for] contemplation. 1
Maharal adds that towards oneself, one should act with Temimus; but not towards others [just as Yaakov said when it became necessary, "I am [Lavan's] match regarding trickery!" (Rashi to 29:12)]. Towards others, one should act as a Yashar.
Rashi writes: "Tam - [Yaakov was] unversed in such deception...." What does the trait of Temimus mean? What did Yaakov merit due to this trait?
Maharal #1 (Nesivos Olam, Nesiv ha'Temimus, Ch 1, p. 206): Temimus means not using schemes, for that would be turning away from HaSh-m [in that a schemer relies on his own intelligence, rather than casting his burden upon HaSh-m]. Therefore, the Tam merits being with HaSh-m, he endures eternally, and his enemies cannot overpower him. Regarding Yaakov specifically, we learn that, "Yaakov Avinu did not die" (Ta'anis 5b); his likeness is engraved on the Kisei ha'Kavod (Bereishis Raba 68:12); he overcame all who opposed him, even angels (Bereishis 32:29).
Maharal #2 (ibid., Ch. 2, p. 208): Due to this trait, Yaakov merited to raise twelve tribes, and that there was no unworthy member among his children.
Rashi writes: "'Dweller of tents' - the tent of Shem, and the tent of Ever." If Yaakov could learn with Shem, who was the elder, why would he choose to [also] learn with Ever?
Gur Aryeh: [When Rivkah had a question to ask, she went to the Beis Midrash of Shem specifically (Rashi to 25:22); because a question should be posed to the greatest authority available.] However, regarding learning, a person should learn Torah from the Rebbe that he chooses, even if he is younger. 1
Perhaps Rashi refers also to later periods in Yaakov's life, after Shem's passing. Shem lived until the year 2158 (when Yaakov was 50). Ever lived until the year 2187. (CS)