Earnestly played by Charles Boyer, Walter Hampden and Leo G. Carroll as Jesuit priests, by William Demarest as a monseigneur and by Lyle Bettger as an agnostic medical man, this film has a special fascination that should appeal to those of contemplative mind.
For what Mr. Lavery is considering, in comparatively simple terms, is the difference between the spiritual and the materialist attitudes. Setting his drama, for the most part, in a Jesuit novitiate, where various degrees of devotion are evidenced among the priests, he brings on a clash of personalities and of basic attitudes over the question of whether an ill person can be miraculously cured.
This question arises when an old priest, seemingly at death's door, gets up from his bed and recovers, which is hailed as a "miracle." However, one wise priest (Mr. Boyer) entertains reasonable doubts, and these are confirmed some time later by the doctor who attends the old man. It seems that the cure was accomplished by something resembling a shock, and the doctor has kept his silence because of his cynical attitude.
Up to this point, Mr. Lavery maintains a reasonable line and carries it through in a series of intellectually stimulating scenes. His characters are solid, credible people, their talk is literate and good, and the quality of their emotions is clearly and tastefully exposed. Furthermore, Mr. Lavery—and Douglas Sirk, who directed his script—continue the tension of the conflict between the doubting priest and the doctor into subsequent scenes.
The priest persists in demanding that the doctor make public the facts, the doctor refuses this exposure, even to settle a lot of swarming pilgrims' minds. But the argument and drama grow fuzzy from this point at which they seem beyond accord, and the whole is brought to a misty ending with a second and seemingly unquestioned "miracle." This latter—the cure of a young lady who undoubtedly has a broken back—brings the priest and the doctor together in a bond of absolute faith.
Link (here) to the full movie review from the NY Times in 1951