- Father Brown: ...believe me. professor, there's no man more dangerous than one who thinks he knows the will of God.
- Father Brown: [talking with Smaill about his assistant] He's married? He has the uncreased look of a bachelor.
- Leonard Smythe: Well, it's refreshing to find a clergyman who doesn't believe in the supernatural.
- Father Brown: No, no, you misunderstand me, Mr. Smythe. I can believe in the impossible but not the improbable.
- Leonard Smythe: I suppose that's what you call a paradox?
- Father Brown: It's what I call common sense. If you tell me Mr. Gladstone in his last hours was haunted by the ghost of Parnell, I can be agnostic about it... but if you tell me that Mr. Gladstone went presented to Queen Victoria, offered her a cigar, and slapped her on the backside, I'd say that was not impossible, but incredible. It isn't the legend I disbelieve in this case.
- John Godfrey: You were there. You saw it. The coffin lid fell of its own accord.
- Father Brown: Nothing in this world happens of its own accord.