Wizard's First Rule: "People are stupid; given proper motivation, almost anyone will believe almost anything. Because people are stupid, they will believe a lie because they want to believe it's true, or because they are afraid it might be true."
Dune: "I must not fear. Fear is the mind-killer. Fear is the little-death that brings total obliteration. I will face my fear. I will permit it to pass over me and through me. And when it has gone past I will turn the inner eye to see it's path. Where the fear has gone there will be nothing. Only I will remain."
LOTR:
Gandalf: “Even the very wise cannot see all ends. My heart tells me that Gollum has some part to play in it, for good or evil, before this is over. The pity of Bilbo may rule the fate of many.'
Frodo: 'I wish the Ring had never come to me. I wish none of this had happened.'
Gandalf: 'So do all who live to see such times, but that is not for them to decide. All we have to decide is what to do with the time that is given to us. There are other forces at work in this world, Frodo, besides that of evil. Bilbo was meant to find the Ring, in which case you were also meant to have it. And that is an encouraging thought.”
J.R.R. Tolkien