GHOST
Revenge his foul and most unnatural murder.HAMLET
Murder?GHOST
Murder most foul, as in the best it is,
But this most foul, strange, and unnatural.HAMLET
Haste me to know 't, that I, with wings as swift
As meditation or the thoughts of love,
May sweep to my revenge.
(1.5.31-37)
Okay, Hamlet sure seems eager enough for revenge here—but this is before he knows who he has to kill (Claudius). Is there something about Claudius that makes Hamlet hesitate? Is he reluctant to kill a king?
GHOST
I am thy father's spirit,
Doom'd for a certain term to walk the night
And for the day confined to fast in fires
Till the foul crimes done in my days of nature
Are burnt and purged away. But that I am forbid
To tell the secrets of my prison-house,
I could a tale unfold whose lightest word
Would harrow up thy soul, freeze thy young blood,
Make thy two eyes, like stars, start from their
spheres,
Thy knotted and combinèd locks to part,
And each particular hair to stand on end,
Like quills upon the fretful porpentine.
But this eternal blazon must not be
To ears of flesh and blood.
(1.5.14-28)
Here, the Ghost claims that he's doomed to suffer in Purgatory (often imagined as a fiery place where souls had to "purge" their sins before they could move on to heaven), until young Hamlet avenges his "foul and most unnatural murder" by killing Claudius. Uh-oh. Major problem alert: First, the doctrine of Purgatory doesn't say anything about murder helping Purgatorial souls get to heaven —prayers, sure, but not vengeance. Second, after the Reformation, Protestants rejected the idea of Purgatory as a "Catholic superstition." You can check out our discussion of "Religion" for more on the play's religious crisis, but here's the point: as a Protestant, Hamlet might see the ghost as just a wee bit suspicious.
GHOST
O horrible, O horrible, most horrible!
If thou hast nature in thee, bear it not.
Let not the royal bed of Denmark be
A couch for luxury and damnèd incest.
But, howsoever thou pursuest this act,
Taint not thy mind, nor let thy soul contrive
Against thy mother aught. Leave her to heaven
And to those thorns that in her bosom lodge
To prick and sting her.
(1.5.87-95)
The Ghost isn't too happy about Gertrude's "damned incest," but he tells Hamlet to keep her out of things anyway. Surprise! Hamlet can't seem to keep this promise, either. In fact, his obsession with Gertrude is so problematic that the Ghost returns in Act III, scene iv, to tell Hamlet to lay off his mom.