“The more you learn about other people, the more you understand yourself; and the more you understand yourself, the more you understand other people.”

“Father Brown got to his feet, putting his hands behind him. 'Odd, isn't it,' he said, 'that a thief and a vagabond should repent, when so many who are rich and secure remain hard and frivolous, and without fruit for God or man?”

“I mean that we here are on the wrong side of the tapestry,' answered Father Brown. 'The things that happen here do not seem to mean anything; they mean something somewhere else. Somewhere else retribution will come on the real offender. Here it often seems to fall on the wrong person.”

“There is a limit to human charity," said Lady Outram, trembling all over."There is," said Father Brown dryly, "and that is the real difference between human charity and Christian charity. You must forgive me if I was not altogether crushed by your contempt for my uncharitableness today; or by the lectures you read me about pardon for every sinner. For it seems to me that you only pardon the sins that you don't really think sinful. You only forgive criminals when they commit what you don't regard as crimes, but rather as conventions. So you tolerate a conventional duel, just as you tolerate a conventional divorce. You forgive because there isn't anything to be forgiven.”

“Are you a devil?""I am a man," answered Father Brown gravely; "and therefore have all devils in my heart.”

“If you try to talk about a truth that’s merely moral, people always think it’s merely metaphorical. A real live man with two legs once said to me: ‘I only believe in the Holy Ghost in a spiritual sense.’ Naturally, I said: ‘In what other sense could you believe it?’ And then he thought I meant he needn’t believe in anything except evolution, or ethical fellowship, or some bilge. . . . -- The Secret of Father Brown”

“The more you learn about other people, the more you understand yourself; and the more you understand yourself, the more you understand other people.”

“Everybody talks about foul dens and filthy slums in which crime can run riot; but it's just the other way. They are called foul, not because crimes are committed, but because crimes are discovered. It's in the neat, spotless, clean and tidy places that crime can run riot; no mud to make footprints; no dregs to contain poison; kind servants washing out all traces of the murder; and the murderer killing and cremating six wives and all for want of a little Christian dirt.”

“No man is such a legalist as the good Secularist.”

“It really is more natural to believe a preternatural story, that deals with things we don’t understand, than a natural story that contradicts things we do understand. Tell me that the great Mr Gladstone, in his last hours, was haunted by the ghost of Parnell, and I will be agnostic about it. But tell me that Mr Gladstone, when first presented to Queen Victoria, wore his hat in her drawing-room and slapped her on the back and offered her a cigar, and I am not agnostic at all. That is not impossible; it’s only incredible. But I’m much more certain it didn’t happen than that Parnell’s ghost didn’t appear; because it violates the laws of the world I do understand.”

“He thought his detective brain as good as the criminal's, which was true. But he fully realised the disadvantage. "The criminal is the creative artist; the detective only the critic," he said with a sour smile, and lifted his coffee cup to his lips slowly, and put it down very quickly. He had put salt in it.”