Genesis 25:34

Then Jacob gave Esau bread and pottage of lentils; and he did eat and drink, and rose up, and went his way: thus Esau despised his birthright. So it was not a mere momentary whim of Esau, for his contempt of his birthright continued even after he had eaten and drunk his fill and was restored to his normal frame of mind. Thus Jacob was filled with a holy seriousness concerning the privileges of the birthright, realizing how much depended upon it in the family of Abraham, while Esau considered the entire matter a joke and acted accordingly. Jacob is a type and example of those that seek the kingdom of God and His righteousness first, while Esau represents such as renounce the eternal blessings for the sake of temporal gain and enjoyment.