What does hamlet learn from the ghosts speech?

Hamlet learns several important things from the ghost's speech. Most significantly, he learns that his father was murdered by Claudius, Gertrude's new husband and Hamlet's uncle. This revelation sets off a chain of events that drives the rest of the play, as Hamlet struggles to avenge his father's death. In addition, Hamlet learns that his mother is aware of Claudius's crime, which shakes his faith in her and further inflames his anger. He also learns that the afterlife is a place of punishment, which suggests that Claudius will eventually be punished for his crime. Finally, Hamlet learns that he has a moral obligation to avenge his father's death, a task that weighs heavily on him and causes him great internal conflict.