Francois Mauriac -

Sin is the writer's element; the passions of the heart are the bread and wine he savours daily. (Literature and Sin)

This could be said of the priest, too.

Here is something, perhaps from the same text, but I cannot remember when I jotted it down thirty years ago or so...

... what the world calls happiness is often a trial without reward, a sterile sufferance, a shining but deserted isle ruled by satiety: a fatal affliction...