(talking to the Ghost who just appaered) What are you, that you walk out so late at night, looking like the dead king of Denmark when he dressed for battle? By God, I order you to speak! 

(explaining Hamlet what happened with the Ghost of his father) After midnight, for two nights running, these two guards, Marcellus and Barnardo, saw a figure that looked very much like your father, in full armor from head to toe. It just appeared before them and marched past them with slow dignity three times, a staff’s distance from their amazed eyes, while they turned, quaking with fear and too shocked to speak. They told me all about this, so on the third night I agreed to come stand guard with them, to see for myself. It happened again, just as they had described. I knew your father. This ghost looked as much like him as my two hands are like each other. 

(talking to Fortinbras, after the slaughter in the finalact) You’ll hear of violent and unnatural acts, terrible accidents, casual murders, deaths caused by trickery and by threat, and finally murderous plans that backfired on their perpetrators. All this I can explain.