This is one of my favorite "Capra-esque" comedies. This movie is just meant to be enjoyed, not deconstructed, microscopically analyzed. It's not religious commentary. It's fun. It's fantasy. The surprisingly negative comments (IMHO) reflect a level of expectation that professional film critics have led us to think must be a part of every movie.
Others have described Travolta's role (it's the reason you'll watch the movie over and over) and the excellent supporting cast (including Sparky!).
Sometimes a cigar is just a cigar; sometimes a movie is just fun.
Enjoy!