Took this from Lostpedia, relating to the mysterious man (Jacob's enemy). I found it quite interesting.
The casting call described him as "Samuel. Any ethnicity, 40s-60s. A corporate raider looking to take over his next company. Powerful, devious and obtuse. He has a cunning intellect and a strong sense of danger. May lead to recurring. Looking for someone very interesting and very special for this role..."
The actions of this individual closely resemble those of the "Un-Man", the demonic spirit controlling Professor Edward Weston in C.S. Lewis' planetary romance Perelandra. In the novel, the Un-Man entered an island planet by taking possession of a dead man, and did not take direct action, but rather worked through trying to persuade another to commit an evil act. This persuasion involved questioning the motivations of a being who had until then been considered an undisputed spiritual authority.
In the Bible, Jacob's brother, with whom he has a tenuous and sometimes antagonistic relationship, is named Esau.
http://lostpedia.wikia.com/wiki/Jacob%27s_enemy