ייִדישער מחשבֿה אויף בראשית 25:31

And this explanation is forthcoming in the words of our sages of blessed memory (Bava Bathra 16b) to the effect that on that day Abraham had died and Jacob was cooking a lentil dish for the mourner's meal. Esau, it seems, was not present at Abraham's demise at all, his eye had shed no tear for his death, and his heart had not broken over Isaac's mourning, but he related to them heartlessly and shamefully and pursued his frivolities in the field. Even when he chanced to come home and found Jacob busy preparing the mourner's dish for his father, he did not sit down, as was the custom, to nod his head in woe and to console, but he shouted out in the manner of the carousers (Genesis 25:30): "Pour me some of this red, red stuff!" That is, I'll open my mouth, and you pour it down! (as Rashi explains). And when Jacob saw him thus abhorrently demeaning his fathers, he was extremely pained that Isaac's honor should be more deeply stamped upon Esau than it was upon himself. For the respect due the elder son by the younger derives from the father's image being more deeply stamped and impressed upon the former in point of his being "the first of his strength." For this reason the younger brother is required to honor the elder, as our sages have explained (Kethuvoth 103a). But if Esau demeaned his fathers, how could their honor be more deeply impressed upon him than upon Jacob! For this reason, Jacob, seeing the evil of his ways, said to him: Because I consider my fathers the crown of my glory, and because (49)"As this day" I relate to them more deeply than you do (Genesis 25:31): "Sell as this day your birthright to me." That is, let our relationship to our father in the days to come be as it is this day. For it is not right that you walk around all day with the stench of your field and I follow in the footsteps of our father, and yet, whenever you feel like it, you vaunt yourself, saying that our father's name is more deeply impressed upon you than upon me.