It's kind of a cheesy scene, and a little melodramatic. But it's a turning point in the movie, and a turning point for the minister, a major character in the film.
If you aren't familiar, it's about a small town with a powerful, wealthy woman (Pollyanna's Aunt Polly) running a large part of the town's business, including telling the minister what he should preach about. Pollyanna shows up and makes a sad town into a happy town. (It is a Disney movie, of course.)
My parents bought us a VHS copy of this when we were little, and we watched it quite a few times. We didn't have cable, so we watched movies like this a lot. I think I've seen this movie 20 times. (I remember trying to destroy the movie because I hated it so much. I'm glad, now, that I failed.)
So, who cares about an old Disney movie?
I suppose the point of all of this isn't religious conversion. It isn't really a religious message. It's the Abraham Lincoln quote:
I think this is a really useful way of cultivating positive relationships with students. It's sometimes easy to see the "bad" in students. I think we can all tell stories about students who struggled in school. It's much more useful, and much more effective, to look for the good. If your goal is to be an effective teacher, noticing and focusing on the "bad" can make you seem negative, pessimistic, and adversarial. Focusing on the positive can help the student like you more, help you like the student more, and help you develop the kind of relationship that can turn into the leverage you need to manage a challenging situation or control a classroom.
If you look for the bad in mankind and expect to find it, you surely will.
I'm not advocating a false sense of positivity. Teachers need to be realistic when they reflect and assess their own teaching. But they also need to be leaders and managers of people. And I think people respond better when you are trying to like them - not trying to find reasons to dislike them.