The central character in Hamlet is charged with a duty to avenge his father, but in the broader sense, he is to avenge the natural order and so restore it. That natural order has been rent asunder by the murder of the king, and Hamlet is the instrument of divine justice who is told to destroy Claudius and Gertrude and so to set things right. Yet, Hamlet does not act immediately, and instead he devises his ploy of a play-within-a-play and also toys with various characters as he prepares his revenge. One such instance of this occurs when he is speaking to Rosencrantz and Guildenstern in Act III Scene 2, two men who are ostensibly his friends and yet who have been ordered by Claudius to kill Hamlet. He knows this, and they do not now that he is aware of the fact. The banter in this scene therefore has a double meaning throughout, and Hamlet takes delight in confusing his supposed killers and in using them as a means of sending a false message about his ambition and his intent to others in the court.
At the beginning of Hamlet, the kingdom may seem calm but is actually in turmoil, and the nightly appearance of the Ghost underscores rather than causes this turmoil. In Hamlet the disorder in the kingdom derives from the fact that the natural order has been challenged--a king has been murdered by his wife and brother, and Hamlet is to act to restore the natural order by avenging his father. The appearance of the Ghost at the beginning of the play shows the degree to which the natural order has been sundered. Hamlet is told what to do by the ghost of his father, whom he meets on the ramparts at night, a portent to all of things to come. Hamlet is called upon to kill Claudius and so to revenge his fathers' death. and this act will also restore order to the kingdom.
Yet, as noted, Hamlet does not immediately carry out this task. Much has been made of his hesitation, and many critics find that his supposed hesitation is due t...