In signature Hitchcock fashion, we know from the start whodunnit, so the film is about something else. The story opens with a murder by the man named Keller who works in a Catholic church in Quebec as caretaker, who proceeds to make confession to the priest, Father Logan (Montgomery Clift). That "something else" is essentially the question, "Will a man lay down his life for something he believes?" This is what it appears Father Logan might have to do because he cannot break silence with regard to Keller's confession of being the killer.
There is, of course, the love interest, and Anne Baxter is perfectly cast for this. The secret nature of her relationship with Father Logan puts increased suspicion on the priest so that by coming forward to the police (Karl Malden is excellent as Inspector Larrue) she inadvertently dooms him by trying to be helpful.
1) The black and white film helps amplify the gloom and doom in the story. There is something dramatic about superb B&W photography, and that "something" carries over to film.
2) There are just so many really powerful camera angles and cool shots.
3) Hitchcock treats religion with respect. The Church is part of the culture, and Hitchcock treats the institution as honorable. Father Logan acts heroically in the face of a great temptation to do otherwise by breaking silence and clearing his name.
Things I didn't like:
1) Father Logan's anguish as he goes for his solitary walk later in the film comes across as a bit melodramatic. One understands the pressure he is under, but the attempt to convey it this way comes off as hokey by modern standards. It did, however, give Hitch the opportunity for some really great camera angles and cool shots.
2) Could the flashback scene have been told a better way? It did, however, convey important information in the story.
This is not a film with witty Cary Grant quips. It is a but more serious and not scary in the typical Hitchcockian way. But it has his fingerprints all over it, and I do confess, I enjoyed it.
SPOILER ALERT: The scene I liked most was when Father Logan exited the courtroom near the end of the film. (Yes, he had to stand trial.) The jury found him innocent. The judge announced that he disagreed with the verdict, but that Father Logan was a free man. But when Logan emerged to the light of day, it was apparent that in the court of popular opinion he was going to be crucified. This scene said a lot.
If you get a chance, add it to your list.