In parashat Toldot we gain further insight into the coming spiritual showdown between the LORD and the serpent (nachash). Recall that the original promise of the coming Messiah was given within the context of the curse and judgment upon Satan: "I will put enmity (אֵיבָה) between you and the woman, and between your seed and her seed; he (i.e., the Savior/Messiah) will crush your head (ראשׁ), and you (i.e., the serpent/Satan) will crush his heel (עָקֵב)" (Gen. 3:15). The very first prophecy of Torah therefore describes the coming of the "Serpent Slayer" and the great conflict of the ages. Since the Messiah would be "born of a woman," the prophecy implies perpetual warfare between those descendants of Eve who shared her faith and underwent teshuvah (called the "children of light" or "children of the promise") and those descendants of Eve who refused it (called the "children of darkness" or "children of the devil"). The ongoing enmity between these "two seeds" foretells the "tale of two kingdoms," the Kingdom of God (מַלְכוּת אֱלהִים) and the kingdom of the devil (John 8:34-36).
After Abraham was tested with the Akedah, he was promised to the heir of the world to come (Rom. 4:13). Genesis 22:18 clearly states that the blessing would come through Abraham's "seed" (זֶרַע), and indeed Abraham later bequeathed everything to his son Isaac (Gen. 25:5). Isaac and Rebekah had been married for twenty years but were still without an heir to carry on the family line. Finally their prayers were answered and Rebekah conceived, though her pregnancy was not without complications: "The children struggled together within her (וַיִּתְרצֲצוּ הַבָּנִים בְּקִרְבָּהּ), and she said, 'If it is thus, why is this happening to me?' So she went to inquire of the LORD" (Gen. 25:22). The LORD then told Rebekah (through the prophet Shem) that she was carrying twin sons who would father two great nations of opposite ideology and origins, though the younger child would be chosen as the heir of the godly line leading to the Messiah. The struggle within Rebekah's womb therefore recalled the original prophecy of God made in the Garden of Eden and the future conflict between the two "seeds." Note that the word translated "struggled" in this verse is ratzatz (רָצַץ), a verb used elsewhere to express violent conflict (e.g., to oppress (Deut. 28:33; 1 Sam. 12:3; Jer. 22:17), to crush (2 Kings 23:13), to break (Isa. 36:6), etc.).
Rashi quotes a fanciful midrash that says that when Rebekah would pass by the doorway of a House of Learning, Jacob fought to be born and enter it, but when she passed a temple devoted to idol worship, Esau fought to get out. The battle between the sons, in other words, would fundamentally represent the ongoing enmity between the children of light and the children of darkness (as would be revealed in later narrative of the Torah).
When the time came for Rebekah to give birth, the first child came out with a full head of hair and ruddy complexion. Since he looked like a child who had been born long before, he was named Esav (from asah [עָשָׂה], meaning "made," or "completed"). His twin brother then came out holding his heel, and therefore was dubbed Ya'akov (meaning "heel holder" or "grappler"). It is interesting to note that Esav's name comes from the same root used to describe "works," whether human or divine. The spirit of Jacob was protesting from the moment of his birth that his twin brother Esau was "complete" and that his works would be sufficient apart from divine intervention. Isaac immediately favored Esau, presumably because he was the firstborn; but Rebekah, believing the promise of the LORD, favored Jacob. We have to wonder why Isaac did not believe the message given to Rebekah regarding the twins. Did Isaac associate the name Ya'akov (grappler of the heel) with the original prophecy given in the Garden ("he shall bruise your heel [עָקֵב]")? If Isaac believed that the Messiah would come through his line, perhaps he associated the image of Jacob attacking the heel of his brother as a bad omen....
The question is raised as to why God chose Jacob and rejected Esau. If, as the New Testament affirms, Jacob was sovereignly chosen "before the children were born," how could Esau have overcome his natural tendencies to become righteous (see Rom. 9:11-12)? The sages remind us that both children grew up in a godly home, with virtuous and loving parents. Indeed, according to Rashi, throughout their youth they were "indistinguishable" in their goodness and virtue. It was only after the death of Abraham that Esau chose the path of impurity (according to tradition it was at this time that he sold his birthright for some stew). And yet (as any parent with a wayward child knows) this might explain why Isaac refused to let go of his hope for Esau. "According to the pain, is the reward" (Avot 5:22). Had Esau overcome his evil inclination during his adult years (as he had done in his youth), he would have been stronger than Jacob, who was described as ish tam yoshev ohalim, "a wholesome man, who lived in tents" (i.e., naturally inclined to holiness). As was later clearly revealed, however, Esau chose the path of darkness and made himself into an enemy of God's greater purpose of redemption. Like Cain before him, he was of the "seed of the serpent," and God therefore sealed his fate by rejecting him (Mal. 1:2-3; Rom. 9:13).
As mentioned elsewhere (see "The Deception of Esau"), it took a long time for Isaac to "open his spiritual eyes" to discern the truth about his two sons. During the dramatic episode of the "stolen blessing," some have suggested that Isaac actually knew he was blessing Jacob but "pretended" to be fooled in order to avoid destroying his relationship with his firstborn son Esau.... Isaac's blindness is central here: when he regarded his sons using his physical sight, he favored Esau, but when he looked away from the realm of appearances, he was empowered to appoint Jacob as the heir of the promise of God...