I don't know as I'm not familiar with this short story. It could be ordinary people who are devout believers in the good lord, or it might be someone in a particular difficult situation, like a struggling family or an individual facing a crisis. But this is just speculation without reading the story.
Since I haven't read the story, I can't say for sure who the main characters are.
Without reading the story, it's impossible to accurately name the main characters. However, given the title, it might be characters who are in a position of need and are relying on the good lord to provide. They could be from any walk of life, perhaps a farmer waiting for a good harvest which he believes the good lord will provide, or a sick person hoping for a cure that they think the good lord will send. But again, this is just guesswork.