As soon as Polonius exits the scene, Claudius laments about his inability to pray and the guilt he is experiencing after murdering his brother. As Claudius proceeds to contemplate his sin and wonder whether or not he can ask God for forgiveness, he kneels down as Hamlet silently enters the room. Knowing that he has a perfect opportunity to kill King Claudius, Hamlet draws his sword. However, Hamlet hesitates and says,
"And so he goes to heaven. And so am I revenged.—That would be scanned. A villain kills my father, and, for that, I, his sole son, do this same villain send To heaven. Oh, this is hire and salary, not revenge" (Shakespeare, 3.3.75-80).
Hamlet refuses to kill Claudius while praying, because he believes that Claudius's spirit will go to heaven since he is in the process of asking God for forgiveness. Hamlet knows that his father never had a chance to repent for his numerous sins before Claudius murdered him and does not think that sending Claudius's soul to heaven would be adequate revenge. Essentially, killing Claudius is not enough for Hamlet, who wishes to send Claudius's soul to hell for eternity. Hamlet hopes to kill his uncle while he is excessively drinking alcohol, gambling, or "in th' incestuous pleasure of his bed" in order to ensure that his soul will suffer in hell.