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. 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. 32 And Isaac his father said unto him, Who art thou? And he said, I am thy son, thy firstborn Esau. 33 And Isaac trembled very exceedingly, and said, Who? where is he that hath taken venison, and brought it me, and I have eaten of all before thou camest, and have blessed him? yea, and he shall be blessed. 34 And when Esau heard the words of his father, he cried with a great and exceeding bitter cry, and said unto his father, Bless me, even me also, O my father. 35 And he said, Thy brother came with subtilty, and hath taken away thy blessing. 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?
As I mentioned previously, Isaac immediately pieced together what transpired once he was greeted by the real Esau, so he must have still had his suspicions all the way through giving Jacob the first blessing.
And as for Esau, even amidst his anguish his chief concern was that he still receive some sort of blessing. His words “hast thou not reserved a blessing for me?” further shows his misunderstanding of how blessings work. He seems to believe that it us up to his father to produce and give out blessing as if they could be pulled out a bag.
Esau does not appreciate that true blessings are the immutable word of God, given and withheld entirely at His choosing. Thus the blessing that Esau ends up receiving is not some backup gift his father conjured up, it is the original blessing that was always intended for him by God.