The Torah testifies in Parshas Toldos (26:5) that Avraham kept the Torah before it was given. "Because Avraham obeyed My voice, and observed My safeguards, My commandments, My decrees, and My torahs". Rava teaches (Talmud Yoma 28b) that the above verse even includes eruv tavshilin (the procedure enabling one to cook on a festival (yom-tov) that falls on a Friday, to prepare food needed for Shabbos). How then could Avraham purchase Meoras Hamachpeila for only "four hundred silver shekels in negotiable currency", and how could Yaakov purchase the b'chora for bread and lentil stew, when both patriarchs knew the true value of their respective purchases? Why were these transactions not in violation of the Torah law (Vayikra 25:14) "Al tonu" ("do not aggrieve one another")?
The late Rav Eliyahu Michkovsky zt"l of Kfar Chasidim answers with the following insightful story. There once was a Jewish man in need of financial assistance to marry off a daughter. When he asked his rebbe for a blessing, the rebbe advised him that he should avail himself of the first business opportunity that presents itself, for in that deal Hashem's blessing would be found. On the way home, at an inn, a group of businessmen were meeting. When they noticed him, one of them, wishing to have a good time, offered him the opportunity to purchase his share of olam habah for a ruble. The Jew in need immediately recalled his rebbe's advice and accepted the deal. They drew up a contract, it was signed, and the ruble changed hands. When the seller came home and told his wife of the proceedings, she immediately berated him and insisted he re-negotiate with the purchaser, as she would not stay married to a man who had no "olam habah". When he found the purchaser, the latter refused to reverse the sale. The seller had no recourse but to appeal to the buyer's rebbe that he instruct his disciple to reverse the sale, as the seller's marriage depended upon it.
The rebbe of the buyer ruled that by the letter of the law his disciple was justified in maintaining the status quo; however, for the right price, perhaps the buyer could be persuaded to change his mind. The rebbe informed the seller that the purchaser needed to marry of his child, and if the seller would assist in financing the marriage, the purchaser would re-negotiate. Indeed that is what happened. Upon leaving the rebbe, the seller asked, "Yesterday the buyer paid me a ruble for the merchandise. Is it fair that I have to now pay several thousand fold?!" The rebbe responded that the cost of the merchandise was determined by its worth. Yesterday, the seller scorned the worth of olam-haba and thus its worth was but a ruble; currently, his assessment and appreciation of olam-haba was much greater and the price reflected this.
The Torah teaches (Toldos 25:34) that Eisav spurned the bechora (birth right), thus the bread and stew were appropriate payment. Similarly, the Zohar in Parshas Chayei Sarah teaches that Efron looked into the cave of machpeila and only saw darkness; when Avraham looked in he saw light. Efron thus received a very fair price for his darkness, while Avraham was purchasing the entrance to Gan-Eden.
If one has respect for a concept, then it will abide with him and enhance him. However, if he is disrespectful of it, it abandons him. Eisav showed disdain for the b'chora and thus it was taken from him. Yaakov, who showed great respect for the b'chora, became its natural possessor.
We find this concept in the Talmud (Berachos 62b), where we are taught that Dovid showed disrespect for clothing (by cutting the corner off Shaul's garment (Shmuel I, 24:5). When Dovid was old although he was covered with garments, they could not warm him.
We celebrate in this month of Kislev the yom-tov of Chanukah. The Bach in his commentary on Shulchan Aruch (Ohr Hachaim 670) asserts that at the time of the second Beis Hamikdosh the Jews "nisrashlu ba'avodah", were lax in their Temple service (they neither appreciated it nor honored it properly). For this reason they almost lost it, and were forced to fight for it. Once they showed that they were moser nefesh (willing to give their lives) for the Beis Hamikdosh, demonstrating their appreciation thereof, they were worthy of repossessing the Temple.
[Similarly, the Medrash Rabbah (Braishis, Chapter 63) based on the verse "Yaakov said, swear to me as this day" (25:33) teaches that Yaakov sacrificed on behalf of the b'chora.]
Shabbos is a gift from Hashem to Bnai Yisroel. In accordance with our appreciation, reverence of, and mesiras nefesh for the Shabbos, will be our portion and experience of it. Thus, especially this time of the year, with Friday being a short day, one should avoid traveling on Friday afternoon, lest it lead to an unexpected violation of Shabbos. The care to refrain from discussing and reading business and other secular matters on Shabbos demonstrates our proper assessment of Shabbos, and thus enables one to experience its sanctity.
Finally, in the realm of relationships between spouses, parents, and children, one has to be careful not to emulate Eisav's trait of scorning. One honors a relationship not only by devoting time to it, but also through prioritization. To work hard at earning a living for ones' children at the expense of meaningful and qualitative time such as joint acts of chessed and family Torah study, is a form of scorning these most potentially precious relationships.
In one verse the Torah communicates it all - "Vayivez esav es habechora." Eisav spurned the b'chora therefore Hashem took it from him; Yaakov valued the b'chora and honored it, and therefore Hashem sees to it that the b'chora is still honoring Yaakov.