How we cite our quotes: All quotations are from Thor.
Quote #1
ODIN: Thor Odinson...you have betrayed the express command of your king. Through your arrogance and stupidity, you've opened these peaceful realms and innocent lives to the horror and desolation of war! You are unworthy of these realms, you're unworthy of your title, you're unworthy... of the loved ones you have betrayed! I now take from you your power! In the name of my father and his father before, I, Odin Allfather, cast you out!
If you're going to exile someone, this is the way to do it: thundering shouts followed by a blaze of special effects. And Thor still doesn't seem to get it.
Quote #2
LOKI: You know, it all makes sense now, why you favored Thor all these years, because no matter how much you claim to love me, you could never have a frost giant sitting on the throne of Asgard!
In some ways, Loki has always been exiled. He is a frost giant, after all, and he never quite fits in in Asgard. Exile doesn't need to be physical: it can be spiritual too.
Quote #3
THOR: Can I come home?
LOKI: The truce with Jotunheim is conditional upon your exile.
THOR: Yes, but couldn't we find a way?
LOKI: Your mother has forbidden your return.
Okay, so Loki's being a lying liar from Liarsville here. But as self-serving as they are, his lies actually serve some good. He's forcing Thor to accept his exile, and in so doing, allow Thor to take responsibility for what he's done. That's the first step to becoming a better man…something Thor needs to do if he ever wants to come home.