What did the blessing given to Jacob actually mean for his inheritance and lineage?
Jacob's blessing carried a double portion of his father Isaac's wealth for his inheritance, the material side of the whole picture, and it placed him in the line of the Messiah. That material blessing, not the birthright, produced the enmity between the brothers.
Les teaches that this blessing was not the birthright but the material side of the whole picture. The material blessing provided that the eldest son would receive a double portion; if there were three sons, the estate was divided into four parts, with the oldest getting two and the others one each. For Jacob, that meant he would receive a double portion of the wealth of his father Isaac, for these people were wealthy in their time, with flocks, herds, and servants. It also meant Jacob was now in the line of the Messiah, which meant nothing to Esau. Esau was interested in the double portion and became upset when he learned the blessing had already been given to Jacob. The birthright itself did not create the enmity; the blessing did, and there was no enmity between the brothers from age 24 to 77.