To rush into explanations is always a sign of weakness.

You regard it as impossible that a sinner should be struck down by the wrath of God! I do not!

It is curious - but you cannot make a revolution without honest men. ... Every revolution has had its honest men. They are soon disposed of afterwards.

The tragedy of life is that people do not change.

It is a curious thought, but it is only when you see people looking ridiculous that you realize just how much you love them.

Vous eprouves trop d'emotion, Hastings, It affects your hands and your wits. Is that a way to fold a coat? And regard what you have done to my pyjamas. If the hairwash breaks what will befall them?' 'Good heavens, Poirot,' I cried, 'this is a matter of life and death. What does it matter what happens to our clothes?' 'You have no sense of proportion Hastings. We cannot catch a train earlier than the time that it leaves, and to ruin one's clothes will not be the least helpful in preventing a murder.

the detective's highest talent lay in the gentle art of seeking favours under the guise of conferring them!