How we cite our quotes: All quotations are from Thor.
Quote #1
ODIN: With the last great war ended, we withdrew from the other worlds and returned home at the Realm Eternal, Asgard. And here we remain as the beacon of hope, shining out across the stars. And though we have fallen into man's myths and legends, it was Asgard and its warriors that brought peace to the universe. But the day will come, when one of you will have to defend that peace.
Odin's very clear from the beginning what's expected of Thor and Loki: keep this place safe, because war and horror really stink. They can't say that they don't know how to behave properly.
Quote #2
THOR: When I am king, I'll hunt the monsters down and slay them all! Just as you did, Father!
ODIN: A wise king never seeks out war. But he must always be ready for it.
Again, Thor can't claim he doesn't know how to do the right thing. Odin spells it all out for him.
Quote #3
HEIMDALL: Be warned, I shall uphold my sacred oath to protect this realm as its gatekeeper. If your return threatens the safety of Asgard, my gate will remain shut and you will be left to perish on the cold waste of Jotunheim.
Heimdall, at least, hasn't taken his eye off the ball. Here he spells out his personal ethics—duty before everything—and has the courtesy to let the others know what that means for them. Nice of him to do that.