Calvary is of a type with Heaven Is For Real, a movie about a religious subject but not really a religious movie. It isn't trying to sell you anything, except maybe that people are complex and troubled and worthy of sympathy almost whatever they do.
Brendan Gleeson plays an Irish village priest who is more humanistic than spiritual, who is told by a man in the confessional that the man intends to kill him, Gleeson, a week from Sunday. He knows who the man is, though we do not, but knows neither what to say to him nor what to do about him. Though his superior points out that a technicality relieves him of the confidentiality of confession. As far as I could tell, Gleeson does nothing but go about his usual religious duties while waiting for some kind of inspiration that isn't coming.
Gleeson's suffering is his regular experiences with a vivid variety of characters who don't respect him much and aren't likely to be of any help. There's the local aristocrat who gets no happiness from his wealth but can't overcome his capitalistic greed; his own daughter who can't communicate with him for reasons neither he nor we understand; his only real friend, who is an atheist; and his dog, who is dying. All well conceived and portrayed, none happy but none villainous.
In the current fashion, the scenes are excellent but we don't seem to be going anywhere. The Irish dialect threw me a little, but also threw a woman in the audience who had lived in Ireland, so I was consoled by that.
I think there's something in Calvary about people needing rules to live by, but it's clear that you're intended to figure out what it's all about for yourself.