How we cite our quotes:
You did supplant your brother Prospero.
True: And look how well my garments sit upon me;
Much feater than before: my brother's servants
Were then my fellows; now they are my men.
But, for your conscience?
Ay, sir; where lies that? (2.1.29)
Antonio comes easily to his acts of betrayal because he has no conscience, or at the least he represses it well. (Actually, we think he doesn't have one.) Antonio is an example of how one's conscience can get worn out; evil acts become easier and easier with practice.
Now, good angels
Preserve the king. (2.1.27)
Gonzalo is loyal to a fault. On hearing that big monsters are running around the island, he calls upon the angels to protect not all of them, or just him, but the king. Is this a hint that Gonzalo suspects Sebastian and Antonio are plotting to betray Alonso?
I say, by sorcery he got this isle;
From me he got it. if thy greatness will
Revenge it on him,—for I know thou darest,
But this thing dare not,— (3.2.7)
If we can believe what Caliban says, then Prospero won the isle from him through betrayal. Why then does Caliban not dare to betray Prospero? Is it anything more than the pinches and cramps he knows he'll get as punishment?