Why Did Esau Lose The Blessing?
With the assistance (and insistence) of his mother Rebekah, second-born Jacob (although not by much - his elder brother Esau was his fraternal, most definitely not identical, twin) received his father Isaac's blessing by a masquerade perpetrated on a blind man. Perhaps a legal "loophole" (if not that, something else, because Isaac let the blessing stand after he discovered that he had been deceived about which of his sons that he was actually blessing) was that although Isaac thought that he was speaking to Esau, Esau's name is not mentioned in the blessing itself; Isaac said only "my son," of which Jacob qualified (see also Blessing The Favorites):
"27:26 And his father Isaac said unto him, Come near now, and kiss me, my son. 27:27 And he came near, and kissed him: and he smelled the smell of his raiment, and blessed him, and said, See, the smell of my son is as the smell of a field which the LORD hath blessed: 27:28 Therefore God give thee of the dew of heaven [see Heavens Below, Heavens Above], and the fatness of the earth, and plenty of corn [i.e. grain; see Corn] and wine: 27:29 Let people serve thee, and nations bow down to thee: be lord over thy brethren, and let thy mother's sons bow down to thee: cursed be every one that curseth thee, and blessed be he that blesseth thee." (Genesis 27:26-29 KJV)
"Thy brother came with subtlety, and hath taken away thy blessing"
When Esau returned from the deer hunt that Isaac had sent him on before Isaac's intended blessing of Esau, the deception was discovered, much to the grief and anger of both Isaac and Esau. But Isaac regarded the blessing as legally binding i.e. "I have eaten of all before thou camest, and have blessed him? Yea, and he shall be blessed."
"27:30 And it came to pass, as soon as Isaac had made an end of blessing Jacob, and Jacob was yet scarce gone out from the presence of Isaac his father, that Esau his brother came in from his hunting. 27:31 And he also had made savoury meat, and brought it unto his father, and said unto his father, Let my father arise, and eat of his son's venison, that thy soul may bless me.
Esau then pleaded with Isaac for a blessing - and got one. The difference however was that Esau then received the blessing that Jacob apparently would have received as the younger son.
"27:36 And he said, Is not he rightly named Jacob? for he hath supplanted me these two times: he took away my birthright; and, behold, now he hath taken away my blessing. And he said, Hast thou not reserved a blessing for me?
Fact Finder: What does the New Testament say about Esau's loss of the blessing? Does it say that he was a "victim" - or that he lost it because he was irresponsible and unworthy of the blessing?