Act 1, Sc. 5, lines 25-32: What does the revelation made by the Ghost mean for Hamlet?

Hamlet: O God!

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.