Good But Dangerous

In the popular imagination, labeling a person as "good" can be a way to dismiss them.  The playground taunts of someone as a "goody-goody" or a "goody two-shoes" imply that they are over-scrupulous or even over-concerned with the appearance of goodness as if to curry favor with those in power.  The stereotype is perhaps to say that a "good" person is an obedient rule-follower, boring and insipid, lacking in imagination and drive; they are predictable and easily taken advantage of.  They will surely finish last.  Indeed, there can be something almost offensive in their seeming inoffensiveness. 

But Lewis and Tolkien, each in their own way, decouple the ideas of goodness and safety in their fiction – both naturally and implicitly in the worlds they have created, and also expressly in reported dialogue.  

Here the Beavers are telling Peter, Susan, and Lucy about Aslan (whom we have not yet met) in chapter 8 of The Lion, the Witch and the Wardrobe (emphasis added):

"Ooh!" said Susan, "I'd thought he was a man. Is he – quite safe? I shall feel rather nervous about meeting a lion."

"That you will, dearie, and no mistake," said Mrs. Beaver; "if there's anyone who can appear before Aslan without their knees knocking, they're either braver than most or else just silly." 

"Then he isn't safe?" said Lucy. 

"Safe?" said Mr. Beaver; "don't you hear what Mrs. Beaver tells you? Who said anything about safe? 'Course he isn't safe. But he's good. He's the King, I tell you."

(The idea comes back in various forms throughout the Narnia books.  In The Silver Chair, for example, Jill Pole asks Aslan to "promise not to – do anything" to her, if she comes and drinks from the stream; he declines, and proceeds to tell her "I have swallowed up girls and boys, women and men, kings and emperors, cities and realms."  We repeatedly hear that Aslan is not "a tame lion.")

And here's where Gandalf tells Aragorn, Legolas and Gimli about Fangorn, in book III, chapter 5 of The Lord of The Rings (emphasis added):

"But you speak of him as if he was a friend.  I thought Fangorn was dangerous."  

"Dangerous!" cried Gandalf. "And so am I, very dangerous: more dangerous than anything you will ever meet[...].  And Aragorn is dangerous, and Legolas is dangerous. You are beset with dangers, Gimli son of Glóin; for you are dangerous yourself, in your own fashion. Certainly the forest is perilous [...] and Fangorn himself, he is perilous too; yet he is wise and kindly nonetheless."