“Doubt is a pain too lonely to know that faith is his twin brother.”

“When in the down I sink my head,Sleep, Death's twin-brother, times my breath;Sleep, Death's twin-brother, knows not Death,Nor can I dream of thee as dead:”

“Suddenly it was too hard to be in his presence, too painful to know that he would belong to someone else.”

“Gabriel. Number three?" That killed the smile. "Yeah. My twin brother. He says he doesn't care if I go away to school, but I know he does.""Identical twin?""Yeah.""Niiiiice."Nick cut him another look, and Adam smiled. "Sorry.”

“Take faith, for example. For many people in our world, the opposite of faith is doubt. The goal, then, within this understanding, is to eliminate doubt. But faith and doubt aren't opposites. Doubt is often a sign that your faith has a pulse, that it's alive and well and exploring and searching. Faith and doubt aren't opposites, they are, it turns out, excellent dance partners.”

“If faith never encounters doubt, if truth never struggles with error, if good never battles evil, how can faith know its own power? In my own pilgrimage, if I had to choose between a faith that has stared doubt in the eye and made it blink, or a naive faith that has never known the firing line of doubt, I will choose the former every time.”