I have to confess, I found the "Ben Hur" line of dialogue on a wonderful website called "The Greatest Films", which has detailed plot synopses and extensive quotations from hundreds of movies. If you haven't been there, you should definitely check it out:
The Greatest Films
(But be warned: I don't think I've ever gotten more pop-up ads than I get when I go to that website.)
I'm pretty sure I know the movie your scene is from, because it's one of my all-time favorites:
Shadow of a Doubt?