In Hamlet, Claudius resembles Cain, who could not fathom the impetus behind Abel's sacrifices -- Abel's love of God.  Cain was blind to love, and saw only the outward forms, the sacrifices and the rewards.  Cain's devotion to form, and blindness to the love, was interrelated was so radical, that he believed he could obtain the rewards by murding his brother, the object of God's affection.  Put another way, Claudius and Cain share in common an inability to apprehend the oscillation between rhetoric and philosophy.