Since the question does not require any other information than a character list, I'll give you that.
Dr. Calvin Bruce
Bishop Edward Hampton
The above list is in no particular order of importance. It is alphabetical by last name of character. As you can see, several of their last names are the same, so the book not only contains various characters, but individual families are represented as well. Only about half of the above listed characters are central to the story. Reverend Maxwell is important because it is his challenge to his church's congregation and the members of the community that propels many of their future actions. While his challenge of "what would Jesus do?" is a good challenge, it doesn't always work out as intended.
In His Steps is a religious-fiction book by Charles Monroe Sheldon.
The main character is Reverend Henry Maxwell. He has a wife named Mary. He challenges the people around him to ask the question of "what would Jesus do?" before doing anything themself.
Other characters include Edward Norman, Alexander Powers, and Rollin Page, who all follow Maxwell's advice of asking, "what would Jesus do?" This causes them to make what they think are ethical and moral choices instead of what they would have done normally.
A list of a few other characters: Dr. Calvin Bruce, Bishop Edward Hampton, Felicia and Rose Sterling.