Cain was a man who knew God but allowed his own wickedness to take control of him to the point that he murdered his innocent brother Abel. Instead of putting Cain to death, God allowed Cain to wander under a curse that Cain put on himself by allowing sin to control him. God calls wanderers like Cain to come home to Him but requires faith and obedience to really make it work. All the while His mercy and grace are present for the one seeking Him.