Lentil soup is mentioned in the Bible : In Genesis 25:34 , Esau is prepared to give up his birthright for a pot of fragrant red lentil soup being cooked by his brother , Jacob . Lentil soup is mentioned in the Bible : In Genesis 25:34 , Esau is prepared to give up his birthright for a pot of fragrant red lentil soup ( a `` mess of pottage '' ) being cooked by his brother , Jacob .