Esau held a grudge against Jacob because of the blessing his father had given him. And Esau determined in his heart: "The days of mourning for my father are approaching; then I will kill my brother Jacob."
References for Genesis 27:41
When the words of her older son Esau were reported to Rebekah, she summoned her younger son Jacob and said to him, "Listen, your brother Esau is consoling himself by planning to kill you.
So now, my son, listen to me. Flee at once to my brother Laban in Haran,
and stay with him for a few days until your brother's anger subsides-
until your brother's rage turns away from you and he forgets what you have done to him. Then I will send for you and bring you back from there. Why should I lose you both in one day?"
So Rebekah said to Isaac, "I'm sick of my life because of these Hittite women. If Jacob marries a Hittite woman like one of them, what good is my life?"
References for Genesis 27:46