Esau held a grudge against Jacob because of the blessing his father had given him. And Esau said in his heart, “The days of mourning for my father are at hand; then I will kill my brother Jacob.”
Jewish Publication Society of America Version (JPS1917) - Genesis 27:41 >And Esau hated Jacob because of the blessing wherewith his father blessed him. And Esau said in his heart: 'Let the days of mourning for my father be at hand; then will I slay my brother Jacob.'