What are some quotations in Fahrenheit 451 that relate to the topic, "words are powerful", and, more specifically, "words are hurtful"?

Fahrenheit 451, a novel about a dystopian American society in which books are burned and no one is allowed to read, is about the importance of knowledge and the consequences of censorship. 

One important quotation on this topic is by Faber, who says: "The magic is only in what books say, how they stitched the patches of the universe together into one garment for us." By this, he means that the power of books (and words) is that they can bring together all the little things we notice or think into a larger picture of the whole "universe", and all of life, that can tell us who we are, what we are doing, and why it matters. 

That quote can be contrasted to one by Beatty, a fireman, who says: "A book is a loaded gun in the house next door... Who knows who might be the target of a well-read man?" In this passage, Beatty says that the knowledge and ideas in books (and words) are dangerous, because they can make someone powerful. In particular, he says that these words can make someone more powerful than his neighbor, and give him the ability to hurt, or control him (as with a gun).