What did Jacob's receipt of the blessing mean for his place in the messianic line?
Receiving the blessing placed Jacob in the line of the Messiah. This meant Jacob was now in the messianic line, a spiritual reality Esau did not value. The same blessing also carried the material promise that Jacob would receive a double portion of his father's wealth.
Les explains that the birthright itself did not create the enmity; the blessing did, because the blessing was the material side of the whole picture. The material blessing gave the eldest son a double portion of the estate. Esau cared about that double portion and became upset when he learned the blessing had already been given to Jacob. That blessing meant Jacob was now in the line of the Messiah, something that meant nothing to Esau, and it also meant Jacob would receive a double portion of his father Isaac's wealth. These people were wealthy for their day, with flocks, herds, servants, and gold and silver.