What is the main conflict in The Amen Corner by James Baldwin?

After giving a fiery Sunday morning sermon, Margaret is confronted by the unexpected arrival of her long estranged husband, Luke, who collapses from illness shortly thereafter. Their son, David, along with several elders of the congregation, learn from Luke that, while Margaret had led everyone to believe that he had abandoned her with their son years ago, it was in fact Margaret who had left Luke in pursuit of a purely religious life.