Rivkah was pregnant with twins and one would kick as she walked past the house of idolatry and the other would kick as she walked past the house of Torah Study. She didn't know why so she asked people in here village and they didn't know , so she went to ask G-d.
The twins were born but were completely different: one was hairy and came our red and the other was hairless and sweet. Esav was the oldest and became a hunter and the youngest son Yaakov held onto Esav's heel as he wanted to be firstborn, he turned out to spend his time studying Torah.
Esav should receive a Birthright Blessing from Yitzchak (as he is the oldest) ,but one day after coming home from hunting Yaakov is making lentil soup and as Esav is so hungry, Yaakov sells him a bowl of soup for the Birthright.