Horatio Act 1 Post 2

In this scene, the Ghost has entered for the first time and the guards and Horatio try and engage the ghost to speak to them.

Act 1. Scene 1. Lines 103-119
Was gaged by our king, which had (returned)
To the inheritance of Fortinbras
Had he been vanquisher, as, by the same comart,
And carriage of the article designed,
His fell to hamlet. Now, sir, young Fortinbras,
Of unimproved mettle hot and full,
Hath in the skirts of Norway here and there
Sharked up a list of lawless resolutes
For food and diet to some enterprise
That hath a stomach in 't; which is no other
(As it doth well appear unto our state)
But to recover of us, by strong hand
And terms compulsatory, those foresaid lands
So by his father lost. And this, I take it,
Is the main motive of our preparations,
The source of this our watch, and the chief head 
Of this posthaste and rummage in the land.

What's revealed here about Horatio is that he is kinda a political figure in Denmark. He understands what is happening to their country and is taking part. Here he tells us why he is where he is, and why there is commotion and "rummage" in Denmark at this time. Also even though we are way past reading this part, at the time, we got insight into what is happening in Denmark, and how Fortinbras was not being supported and he was "rummaging" up an army of his own to win over the land.

Act 1. Scene 4. Lines 63-65
It beckons you to go away with it
As if it some important did desire
To you alone.

.    .    .  

What if it tempt you toward the flood, my lord?
Or to the dreadful summit of the cliff
That beetles o'er his base into the sea,
And there assume some other horrible form
Which might deprive your sovereignty of reason
And draw you into madness? Think of it.

What is happening here is that Horatio is conversing with Hamlet as the ghost enters. Hamlet is saying that he is going to go alone to speak with the ghost, but Horatio and the other guards do not want to allow that because they fear for Hamlet's safety. What is being revealed here about Horatio is that not only does he certainly not have any more doubts in the ghost's existence, but he understands that the ghost could be dangerous. He wants to support his prince and keep him safe too. Horatio later says "heaven will direct it" (1. 4. 101) meaning that he an sense that something big is happening right now in Denmark, but what they should do is they should just let God take care of it or deal with it.