Once Isaac had given his - really God's - blessing, there was nothing left for Esau. The blessing was an "all or nothing" addition to the inheritance; it could not be portioned between Isaac's two sons. In reality, the subsequent "blessing" Esau receives is tantamount to a curse. In the New King James Version, it reads as if Isaac blesses Esau in Genesis 27:39-40, yet it is not a blessing but a prophecy.
As shown here, the two uses of "of" in verse 39 have been mistranslated; in this context, the Hebrew word implies, not "belonging to," but "from" or "away from." On this verse, the Keil and Delitzsch Commentary on the Old Testament observes, "By a play upon the words Isaac uses the same expression as in v. 28, 'from the fat fields of the earth, and from the dew,' but in the opposite sense, min being partitive [imparting] there, and privative [depriving] here, 'from = away from.'" Thus, Isaac prophesies that Esau's descendants would live in an infertile, arid area.
One consequence of this is prophesied in verse 40: There will be continual strife between the "have," Jacob, and the "have-not," Esau; they would engage in a constant, internecine quarrel over "the fatness of the earth, and of the dew of heaven." More often than not, Jacob would be dominant - until Esau would rebel in frustration and anger. Isaac predicts that they will frequently come to blows, and occasionally, Esau's descendants will enjoy the upper hand for a time.
Esau's utterly human reaction upon hearing Isaac's words is consistent with what we know of his personality: "So Esau hated Jacob because of the blessing with which his father blessed him, and Esau said in his heart, "The days of mourning for my father are at hand; then I will kill my brother Jacob" (Genesis 27:41). Too late, he realized the value of the blessing, and now his entire attention was focused in hatred against his brother. Hebrews 12:15-16 describes his attitude toward Jacob as a "root of bitterness," a profound and deep-set animosity that ultimately corrupts and defiles one who maintains it.
This reveals the mindset of Esau and his descendants, the Edomites. Everything that should have been theirs was now Jacob's, and they will fight until the bitter end of days to get it back! Yet God says it is not to be. His prophecy in the "blessing" allows Esau only occasional supremacy. Since Jacob's seed possessed both the birthright and the blessing, they would normally prevail and ultimately have the ascendancy.
The birthright made Jacob the recipient of a double portion of the inheritance, and the blessing was a gift of God by which the patriarch passed on the promised family blessings. These blessings included the patriarchy - "Be master over your brethren" (Genesis 27:29) - which was now Jacob's! This meant that, upon Isaac's death, the leadership position in Abraham's family passed not to the elder, Esau, but to the younger, Jacob. Esau was left to form his own house, but without the power, position, and wealth inherent within the birthright and the blessing.
In these prophecies, the Bible shows that dominant family traits are passed down to succeeding generations. Therefore, even today, Israelites generally think and behave much like their father Jacob, while Edomites still retain the attitudes and drives of Esau. Though not every Israelite or Edomite will imitate his ancestor's personality to the letter, these traits will surface as national characteristics, allowing perceptive observers to identify their origins and fit them into Bible prophecy.
For Jacob's thefts of the birthright and blessing, Esau hated his brother enough to begin to plot his death! This burning hatred has been passed on from generation to generation ever since that time, for approximately 3,700 years. This, then, provides us with a basic understanding of the contentious relationship between these two peoples.