Esau and Jacob
Isaac had two sons; Esau and Jacob. Esau was a skilled hunter and often lived in the field. Jacob was meek and quiet, and lived in the tents together with his father and mother.
Isaac had greater love for Esau, who treated him with food from his hunt, but Rebecca had a greater love for Jacob. Esau, as the elder son, had the birthright, that is, seniority over Jacob in the blessing from his father.
Once Esau returned from the field tired and hungry. Jacob at that time was cooking himself lentil stew (proverbially called a mess of pottage). Esau said to him, "Feed me."
Jacob said, "Sell me this day thy birthright" since he wanted very much for the blessing that God gave to Abraham to refer to him and in this way to serve God zealously.
Esau answered, "Behold, I am dying of hunger; what do I care about this birthright?" By such an answer Esau showed his careless disregard for God’s blessing.
Jacob said, "Swear to me."
Esau swore to it and sold his birthright to Jacob for a stew of lentils.
When Isaac grew old and blind, sensing that his life was approaching its end, he wished to bless Esau as his elder son. But thanks to the cleverness of Rebecca, he blessed Jacob instead of Esau. Isaac soon learned his mistake, but still confirmed his blessing on Jacob.
Esau hated his brother for this, and even wanted to murder him, so Jacob had to leave his own family.
At the suggestion of his parents, he set out for the homeland of his mother in Mesopotamia, to the land of Babylon, to her brother Laban, in order to live with him until the anger of Esau passed away. While there he married one of the daughters of Laban.
Note: See Genesis, chaps. 23; 24; 25; 27:1-9.
(from: The Law of God by Fr. Seraphim Slobodskoy)