It is often assumed without question that Yaakov bartered the Bechora from Esav for the payment of "Lechem unzid adashim" - I.E. Lentil Soup
Well, I question that premise! The passage does lend itself to that interpretation, but IMHO that is a bit imprecise.
Take Esav's Reaction, it indicates dismissal of Yaakov's proposal as opposed to consent! Esav was seeming to say Take the Bechorah and shove it, and give me dinner because I'm starved! He did not say "Deal!"
So given Esav's reaction - then what WAS Yaakov's proposal? My interpretation is simple. Yaakov was only proposing to NEGOTIATE for the Bechorah WHILE having dinner. And he delayed Esav's dinner long enough to induce Esav to enter into negotiations. Only then Esav dismissed the negotiation completely and GAVE Yaakov the Bechorah - because Esav deemed it worthless anyway. Only then Yaakov proceeded to feed Esav
Go over and parse the P'suqim carefully and see which model you prefer.
To "quid pro quo"
NOT to "quid pro quo"
Did Esav Swap lentils for Bechorah?
Or did he simply refuse to be bothered with any haggling while he was starving and tossed the Bechorah aside.
To be fair to the common perception, Yaakov was taking advantage of Esav's condition, and Esav might have had "seller's" remorse after his appetite had been sated. So the bottom line may SEEM to amount to a "quid pro quo" anyway.