The tone of the scene is pretty ominous. Things aren't going great in Denmark. King Hamlet (senior) has died under mysterious circumstances. Gertrude, his widow, married Claudius, his brother, with unseemly rapidity. Meanwhile, Fortinbras, the young Norwegian prince, is making warlike moves.
If all that wasn't enough, two guards on the night watch have seen what seems to be the ghost of the dead king on the battlements--and they're convinced this is an ill omen.
The guards, Marcellus and Bernardo, have invited the student Horatio, Hamlet's best friend, to join them in their lonely vigil, where for some nights past a ghost has appeared resembling the late King Hamlet, father of the prince who is the main character of the story.
Horatio represents a prototype of modernity, an intellectual familiar with the tradition but skeptical of it. Yet even he must concede the power of the unknown after witnessing the phantom, which he takes as a portent of bad things to come.
Marcellus then points out that there are also sometimes portents of good, particularly at this season of the year:
Some say that ever 'gainst that season comes
Wherein our Saviour's birth is celebrated,
The bird of dawning singeth all night long:
And then, they say, no spirit dares stir abroad;
The nights are wholesome; then no planets strike,
No fairy takes, nor witch hath power to charm,
So hallow'd and so gracious is the time.
At this point, all I can do is say with Horatio something that has become a mantra of mine on many things spiritual, "So have I heard and do in part believe it."
Would that it were so this holiday season and beyond.