Butter

The birthright represents something eternal. A sacred gift imparted by God to the first-born child of each family. Selling the birthright represented the value Esau placed in earthly things that ultimately meant nothing (like a bowl of soup) over a priceless gift, if not more an ordained duty, from the Lord. It reflected Esau's selfish and narrow-minded character that chose a quick fix for his problems -- which eventually caused him great emotional pain and loss -- over a life-long blessing. His character error is similar to that of a married man who, on a business trip, decides in a moment of loneliness to invite a prostitute to his hotel room for an hour of sex. That hour of self-indulgence cost in a weak moment cost the man his intact covenant with his wife as well as a lifetime of guilt, shame and long-term loss of fidelity in his marriage. This transaction represents Jacob's character as manipulative (dangling a "carrot" in front of his desperate brother), self-serving/careless of his brother's needs and discontent. Jacob knew he had a great future, according to what he had learned from his mother. But he still longed for more and apparently would do strive for what he didn't have at any cost.